for key, value in Messages
        {
            PostMessage, nMsg, uID, value,, ahk_id %hWnd%
            Sleep, 50
        }

WM_LBUTTONDOWN = 0x201, WM_LBUTTONUP = 0x202 
PostMessageToTrayIcon("Skype.exe", WM_LBUTTONDOWN, WM_LBUTTONUP)

/*
Send mouse click to tray icon. Example:
PostMessage2TrayIconProcName("processX.exe", "Click Up Right") ; "WM_LBUTTONDOWN" / "RButton" / "RCM Dn" / "Click 2"
PostMessage2TrayIconProcName("proc.exe", [0x204, 0x205]) PostMessage2TrayIconProcName("proc.exe", 0x203)

Limitation:
1) Может работать неправильно, если одновременно происходит пользовательский ввод.
Возможное решение: блокировать ввод на время выполнения.
2) На строке
CurrentProcessName := oWMI.Get("Win32_Process.Handle=" PID).Name
возникает ошибка, если в трее остались иконки прибитых программ.

WM_LBUTTONDOWN = 0x201     WM_RBUTTONDOWN = 0x204     WM_MBUTTONDOWN = 0x207
WM_LBUTTONUP = 0x202       WM_RBUTTONUP = 0x205       WM_MBUTTONUP = 0x208
WM_LBUTTONDBLCLK = 0x203   WM_RBUTTONDBLCLK = 0x206   WM_MBUTTONDBLCLK = 0x209
WM_MOUSEMOVE = 0x200       WM_MOUSEWHEEL = 0x20A      WM_MOUSEHWHEEL = 0x20E
*/

PostMessage2TrayIconProcName(ProcessName, messages)
{
	if (InStr(messages, "C") || InStr(messages, "B")) ; string, contain Click/LButton/LCM
	{
		keyDirectionN := InStr(messages, "D") ? 1 : (InStr(messages, "Up") ? 2 : (InStr(messages, "2") ? 3 : 4))
		whatKeyN := InStr(messages, "R") ? 2 : InStr(messages, "M") ? 3 : 1 ; Right/Middle
		MouseClickWMCodesTable := [ [[WM_LBUTTONDOWN := 0x201], [WM_LBUTTONUP := 0x202], [WM_LBUTTONDBLCLK := 0x203], [0x201, 0x202]]
		, [[WM_RBUTTONDOWN := 0x204], [WM_RBUTTONUP := 0x205], [WM_RBUTTONDBLCLK := 0x206], [0x204, 0x205]]
		, [[WM_MBUTTONDOWN := 0x207], [WM_MBUTTONUP := 0x208], [WM_MBUTTONDBLCLK := 0x209], [0x207, 0x208]] ]
		messages := MouseClickWMCodesTable[whatKeyN, keyDirectionN]
	}
	static WM_USER := 0x400, TB_BUTTONCOUNT := WM_USER + 24, TB_GETBUTTON := WM_USER + 23
		, PtrSize := A_Is64bitOS ? 8 : 4, SizeOfTBBUTTON := 8 + PtrSize*3, SizeOfTRAYDATA := 16 + PtrSize*2
	oWMI := ComObjGet("winmgmts:")
	DHW_Prev := A_DetectHiddenWindows
	DetectHiddenWindows, On

	Loop 2
	{
		ControlGet, hWnd, hwnd,, ToolbarWindow321, % "ahk_class " . (A_Index = 1 ? "Shell_TrayWnd" : "NotifyIconOverflowWindow")
		WinExist("ahk_id" hWnd)
		WinGet, PID, PID

		if (A_Index = 1 && !IsObject(RemoteBuff := New RemoteBuffer(PID, SizeOfTRAYDATA))) {
			DetectHiddenWindows, %DHW_Prev%
			Return, 0, DllCall("MessageBox", Ptr, 0, Str, "Не удалось создать удалённый буфер`nОшибка " A_LastError, Str, "", UInt, 0)
		}

		SendMessage, TB_BUTTONCOUNT
		Loop % ErrorLevel
		{
			SendMessage, TB_GETBUTTON, A_Index - 1, RemoteBuff.ptr
			if ! ( pTBBUTTON := RemoteBuff.Read(SizeOfTBBUTTON) )
				|| !pTRAYDATA := RemoteBuff.Read(SizeOfTRAYDATA, NumGet(pTBBUTTON + 8 + PtrSize) - RemoteBuff.ptr) {
				DetectHiddenWindows, %DHW_Prev%
				Return 1
			}

			WinGet, PID, PID, % "ahk_id" hWnd := NumGet(pTRAYDATA+0)
			CurrentProcessName := oWMI.Get("Win32_Process.Handle=" PID).Name
			if (CurrentProcessName = "AutoHotkey.exe")
			{
				WinGetTitle, Title, % "ahk_id" hWnd
				CurrentProcessName := RegExReplace(Title, "i).*\\(.*) - autohotkey v[\.\d]+", "$1")
			}
			if (CurrentProcessName = ProcessName)
			{
				uID := NumGet(pTRAYDATA + PtrSize, "UInt")
				uCallbackMessage := NumGet(pTRAYDATA + PtrSize + 4, "UInt")
			; BlockInput, On
			; SendInput {Click Up}{Click Right Up} ; hack
				messages := IsObject(messages) ? messages : [messages]
				for i, message in messages
					PostMessage, uCallbackMessage, uID, message,, % "ahk_id" hWnd
			; BlockInput, Off
				DetectHiddenWindows, %DHW_Prev%
				Return 0
			}
		}
	}
	DetectHiddenWindows, %DHW_Prev%
	Return 1
}

Class RemoteBuffer
{
	__New(PID, size)
	{
		static PROCESS_VM_OPERATION := 0x8, PROCESS_VM_WRITE := 0x20, PROCESS_VM_READ := 0x10
			, MEM_COMMIT := 0x1000, PAGE_READWRITE := 0x4

		if !(this.hProc := DllCall("OpenProcess", UInt, PROCESS_VM_OPERATION|PROCESS_VM_READ|PROCESS_VM_WRITE, Int, 0, UInt, PID, Ptr))
			Return

		if !(this.ptr := DllCall("VirtualAllocEx", UInt, this.hProc, UInt, 0, UInt, size, UInt, MEM_COMMIT, UInt, PAGE_READWRITE, Ptr))
			Return, "", DllCall("CloseHandle", Ptr, this.hProc)
	}

	__Delete()
	{
		DllCall("VirtualFreeEx", Ptr, this.hProc, Ptr, this.ptr, UInt, 0, UInt, MEM_RELEASE := 0x8000)
		DllCall("CloseHandle", Ptr, this.hProc)
	}

	Read(size, offset = 0)
	{
		static LocalBuff
		VarSetCapacity(LocalBuff, size, 0)
		if !DllCall("ReadProcessMemory", Ptr, this.hProc, Ptr, this.ptr + offset, Ptr, &LocalBuff, UInt, size, UInt, 0)
			Return, 0, DllCall("MessageBox", Ptr, 0, Str, "Не удалось прочитать данные`nОшибка " A_LastError, Str, "", UInt, 0)

		VarSetCapacity(LocalBuff, -1)
		Return &LocalBuff
	}

	Write(pLocalBuff, size, offset = 0)
	{
		res := DllCall("WriteProcessMemory", Ptr, this.hProc, Ptr, this.ptr + offset, Ptr, pLocalBuff, UInt, size, UInt, 0)
		Return res ? res : 0, (!res) ? DllCall("MessageBox", Ptr, 0, Str, "Не удалось записать данные`nОшибка " A_LastError, Str, "", UInt, 0)
	}
}

#NoTrayIcon
WM_LBUTTONDBLCLK := 0x203
 
PostMessageToTrayIcon("Skype.exe", WM_LBUTTONDBLCLK)
 
PostMessageToTrayIcon(ExeFileName, Messages*)
{
/*
Недокументированная структура TRAYDATA
typedef TRAYDATA
{
IntPtr hwnd;
uint uID;
uint uCallbackMessage;
uint Reserved;
uint Reserved2;
IntPtr hIcon;
}
*/
    static WM_USER := 0x400, TB_BUTTONCOUNT := WM_USER + 24, TB_GETBUTTON := WM_USER + 23
      , PtrSize := A_Is64bitOS ? 8 : 4, SizeOfTBBUTTON := 8 + PtrSize*3, SizeOfTRAYDATA := 16 + PtrSize*2 
      
    hShell_TrayWnd := WinExist("ahk_class Shell_TrayWnd")
    ChildClasses = TrayNotifyWnd|SysPager|ToolbarWindow32  ; классы окон в порядке вложенности
    Loop, parse, ChildClasses, |
        hChild := DllCall("FindWindowEx", Ptr, A_Index = 1 ? hShell_TrayWnd : hChild
                                      , Ptr, 0, Str, A_LoopField, UInt, 0, Ptr)
    WinExist("ahk_id" hChild)
    WinGet, PID, PID
    if !IsObject(RemoteBuff := New RemoteBuffer(PID, SizeOfTBBUTTON))
        Return, 0, DllCall("MessageBox", Ptr, 0, Str, "Не удалось создать удалённый буфер`nОшибка " A_LastError, Str, "", UInt, 0) 
        
    DHW_Prev := A_DetectHiddenWindows
    DetectHiddenWindows, On
    SendMessage, TB_BUTTONCOUNT 

    Loop % ErrorLevel  {  
        SendMessage, TB_GETBUTTON, A_Index - 1, RemoteBuff.ptr   
        RemoteBuff.Read(TBBUTTON, SizeOfTBBUTTON) 
        TraydataOffset := NumGet(&TBBUTTON + 8  + PtrSize) - RemoteBuff.ptr  
        RemoteBuff.Read(TRAYDATA, SizeOfTRAYDATA, TraydataOffset)  
        hWnd := NumGet(&TRAYDATA) 
        WinGet, Name, ProcessName, % "ahk_id" hWnd
        if (Name != ExeFileName)
            Continue 
        uID := NumGet(&TRAYDATA, PtrSize, "UInt")
        nMsg := NumGet(&TRAYDATA, PtrSize + 4, "UInt") 
        Break 
    }
    if (uID = "")
        MsgBox, Иконки указанного приложения не найдено!
    else
        for key, value in Messages
        {
            PostMessage, nMsg, uID, value,, ahk_id %hWnd%
            Sleep, 50
        }
    DetectHiddenWindows, %DHW_Prev%
} 

Class RemoteBuffer
{
   __New(PID, size)
   {
      static PROCESS_VM_OPERATION := 0x8, PROCESS_VM_WRITE := 0x20, PROCESS_VM_READ := 0x10
         , MEM_COMMIT := 0x1000, PAGE_READWRITE := 0x4
         
      if !(this.hProc := DllCall("OpenProcess", UInt, PROCESS_VM_OPERATION|PROCESS_VM_READ|PROCESS_VM_WRITE, Int, 0, UInt, PID, Ptr))
         Return
      
      if !(this.ptr := DllCall("VirtualAllocEx", Ptr, this.hProc, UInt, 0, Ptr, size, UInt, MEM_COMMIT, UInt, PAGE_READWRITE, Ptr))
         Return, "", DllCall("CloseHandle", Ptr, this.hProc)
   }
   
   __Delete()
   {
      DllCall("VirtualFreeEx", Ptr, this.hProc, Ptr, this.ptr, UInt, 0, UInt, MEM_RELEASE := 0x8000)
      DllCall("CloseHandle", Ptr, this.hProc)
   }
   
   Read(ByRef LocalBuff, size, offset = 0)
   {
      VarSetCapacity(LocalBuff, size, 0)
      if !DllCall("ReadProcessMemory", Ptr, this.hProc, Ptr, this.ptr + offset, Ptr, &LocalBuff, Ptr, size, Ptr, 0)
         Return, 0, DllCall("MessageBox", Ptr, 0, Str, "Не удалось прочитать данные`nОшибка " A_LastError, Str, "", UInt, 0)
      Return 1
   }
}

Msgbox % DllCall(A_ScriptDir "\TestDll00.dll\PervertInc", "char", -1, "uint64")

__declspec(dllexport) UINT64 PervertInc(DWORD x) // просто прибавляем единицу, без знака.
{
    return (UINT64)x+1;
}