Hi Andrew,
I'm trying tclsoap with aolserver 4 and fortunately I have not had any problem with "package require SOAP". I simply put this command in one sourced tcl file:
ns_eval package require SOAP
but I'm getting the same problem invoking a web service that works just fine with tclsh, i.e. "Server response is not well-formed XML."
I tracked down the problem to the parse_soap_response proc, but before hacking it I wonder if you have already foun a solution.