Bob Cunnings and I have written an IETF i-d on soap authentication.
It's fairly straightforward. It defines header elements that implement
the HTTP basic and digest authentication schemes, as defined in RFC
Look for draft-cunnings-salz-soap-auth-01 at your nearest IETF mirror.
You can also find it at
The draft is written using Marshall Roses's XML2RFC package, documented
in RFC2629. Accordingly, at the above URL you can find the document in
XML, HTML, and TEXT formats.
Zolera Systems, Your Key to Online Integrity
Securing Web services: XML, SOAP, Dig-sig, Encryption