Why don't SOAP Documents Contain Hyperlinks?
In a pure SOAP system, that is where all accesses are to SOAP-based Web services, then each SOAP document will be an island.
The reason for this is simple: with SOAP a URL is meaningless by itself. The URL just points to a SOAP server. To be useful the URL must be accompanied by the SOAP message.
Note: the SOAP Working Group is currently working on a way to do SOAP HTTP GET.