Unfortunately the support for exec under Win32s is very limited. Most of this is because of Win32s. There are definitely some
improvements that could be made (e.g. letting you start Windows apps), but it is never going to be as good as the Windows 95 or
NT versions. Basically Windows 3.1 doesn`t have a very complete process model, and most of what you see in the DOS window is
done using non-Windows APIs. I could probably get Tcl to do the same things, but it`s going to require a lot of very Windows 3.1
specific coding to get it to work. There are a number of other things that are higher priority, so it probably won`t happen for a while.
I would encourage anyone who really wants this feature to work on it and send me patches. 

-Scott Stanton