Well Andrew, you are in luck.
First of all, TclSOAP probably works just fine in AOLserver 4.0,
exactly the same way it works in tclsh, although I haven't tried it
myself and don't remember whether others have reported success or not.
Which version of AOLserver are you using? Try the latest pre-release
Beata of 4.0 from SourceForge.
And coincidentally, the very same day you posted your question, Vinod
announced his
XML-RPC package for OpenACS.