I did use google (extensively) and this site before posting. Give me some credit! :-)

Despite a few weeks work of searching I haven't found a way do do via any other Perl module than Expect - which doesn't work on a Windows system due to IT::Tty being unavailable.

In terms of psexec, it'll do exactly the same as my script, except mine doesn't need another exe bundled with it. The problem remains though: all I'll get back from it is that psexec completed with error code 0. I wont actually get the return code back from net send, which is my problem, not making the script run as someone else, that part works fine.