Try this example from Planet Source Code, I checked it and it seems to work.
"This is User-Friendly, CPU-Friendly, NON-BLOCKING Standard Input-Output code to grab output of a command line interface program, AND, for the first time ever (in open source in VB), to send input to it as well."
http://www.planet-source-code.com/vb...61262&lngWId=1