create data source (system) in EP 6

Hello,

can someone give me a tutorial or something like that on how to create a system (called data source in EP5) in EP 6.

What I want to do is to implement an external Webservice. So the system I need is one which can handle user-mapping but not only with two credentials.

(I only need the instruction for building the system and not for resolving the mapped data)

Ciao

René