Sending keystrokes to Windows exe programs

Sat Apr 2 12:48:44 EDT 2011

I can start a windows program on Vista with:
>>> import subprocess
>>> dva=subprocess.Popen(DVAname,stdin=subprocess.PIPE)

Unfortunately sending keystrokes with communicate() does not appear to work:
>>> dva.communicate('F2')

this does not produce any result but it does make IDLE become really idle.
 >>> dva.terminate()
however does work fine and kills the program as it should.
Is there a way or do I have to go back to Visual Basic?
Regards,
Alex van der Spek