To compile under AS Perl all you really need is M$ VCC of some variety and A Practical Guide to Compiling C based Modules under ActiveState using Microsoft C++. You just emulate the AS build environment (aka copy all the missing M$ headers etc into Perl/lib/CORE), fixup the environment by running VSVARS32.BAT (Last seen in C:\Program Files\Microsoft Visual Studio .NET\Common7\Tools but you know M$ ;-), occasionally have to copy a DLL into System32 for reasons that totally elude me (and I have never bothered to work out ;-) and nmake and CL.EXE will happily compile all sorts of 'basic' XS stuff ie any vanilla C generally works.

Now I know VCC costs money but it does make Perling on Win32 using Active State Perl a helluva lot easier. You only need an old copy - but you can pick it up new on ebay for between $50-100 US. There were 3 X Visual C++.NET sealed in box for 50 quid buy now a few minutes ago.