Getting recieved XML info into SAP


I’m a beginner with WM and Business Connector and I’m having trouble getting some info into our SAP system.

I’m recieving an XML-document from a partner via HTTP-post and I have created a service that fetches it. But, then, how do I get this info into SAP and an IDOC?

I tried to find a discussion about this but failed and I know this probably is a very simple procedure, but I don’t know how to do it.