So what happens if you make a .bat file:
echo "thePassword" | start c:\runas /user:winuser "program args"

If all else fails, it is possible to start a Perl program which then starts the desired program and acts like a person on the command line. In other words, if you are able to make "X" happen from the command line, Perl can too!

I am no expert on Windows sys admin, but I think that there is some automatic reply thing that can go into a batch file.