SOAP encoding

I have eventually found a good explaination on why this is a very bad idea to use SOAP encoding. SOAP encoding only exists for historical reasons. The SOAP authors didn’t initially have access to XSD so they wrote the SOAP encoding rules, which explain how to serialize an instance of the SOAP data model to a SOAP message. It was left to SOAP implementers to map their own technologies to the SOAP data model. When you create a WSDL binding, you have to specify whether the SOAP messages contain literal or encoded instances of the schema constructs the operations use. If you choose "literal," you are saying that the XML Schema constructs your WSDL definitions refer to are concrete specifications of what will appear in your SOAP message bodies. If you choose "encoded," you are saying that the XML Schema constructs your WSDL definitions refer to are abstract specifications of what will appear in your SOAP message bodies; these can be made concrete by applying the rules defined by SOAP encoding.
And then we can conclude as Tom noticed: "if you use SOAP encoding, then you can't validate the message with an XML Schema, and you can't transform the message using XSLT" this is obviously a bad idea!