Hi Rob,
I'm not a SOAP expert, but I believe this is possible yes, with certain services. Diego showed something similar in Oz recently using Clarion#. From what I understand it's a "default" behavior for .Net based services, although not necessarily a standard.
The most obvious way to do something like this with NetTalk is to make a function that returns the information about your service. However if your approach was "the same" then obviously things are compatible, which is good.
Sean has offered to whip up a .Net service for me to try, so I'll post back some results here in a day or so. Obviously if it's nice an consistent then the template could generate this list automatically, which would be quite cool.
Cheers
Bruce