Create function that receives an XML in the SOAP Server (delphi)

Good morning.
Reading various files, tutorials, etc. on the net, I was able to understand and develop a SOAP server (Delphi 7 and Tokyo). I created several functions to receive values and return answer ..
I created a client (Delphi 7 and Tokyo) and managed to consume without any mystery ALL the functions of the SOAP server through the import of the WSDL that the SOAP server provides. But All the functions that I have developed in the SOAP server receive parameters of type String or integer. Home I would like to make a function in the SOAP SERVER that receives an XML, however I can not find any articles that help me to remedy this need.
Could any of you give me a direction, or tell me something I can read to be more enlightened ?? Sorry if I wrote something out of the context of the SOAP SERVER, but I'm starting in this strange SOAP world now and I do not know the right words yet to describe my need. If it has not been clear enough, please signal or request more information that I will try to clarify in other words.