The problem was solved as following:
I created a button which has VB script:
LoadFile("c:\myfile.txt")
While IsLoading()
Sleep 100
Wend
This button has enabled a HOTKEY (for example key "0").
So when my application finishes, focuses on Mach application
and sends a keystroke "0" (the HotKey).
2-3 days of searching and i didn't find any other solution.
Still if you have any idea of controlling it through Mach,
please share.
Giannis