Hi,
SOAP::WSDL's WSDL parser works on a custom document model. The information you're looking for is included, but you'll have to look through the source to find it, and there's no guarantees these parts of SOAP::WSDL stay as they are, because it's not part of the official API.

The easiest way to get the information you need is to use a DOM parser like XML::LibXML and to use XPath to find the parts you need.
Martin