XML::Compile::SOAP handles the SOAP protocol. The first implementation is
SOAP1.1 (http://www.w3.org/TR/2000/NOTE-SOAP-20000508/), which is still most
often used. The SOAP1.2 definition (http://www.w3.org/TR/soap12/) is provided
via the separate distribution XML::Compile::SOAP12.

Be aware that there are three kinds of SOAP:
1. Document style (literal) SOAP, where there is a WSDL file which explicitly
   types all out-going and incoming messages. Very easy to use.
2. RPC style SOAP literal. The body of the message has an extra element wrapper,
   but the content is also well defined.
3. RPC style SOAP encoded. The sent data is nowhere described formally. The data
   is constructed in some ad-hoc way.