Web AS 6.40 Java connecting to R/3 Basis 620

I'm trying to setup Web Dynpro to work with an older R/3 (620 Basis). However, I did not figure out how to configure a JCo Connection.

Things I did so far:

• Imported the predefined CIM models into SLD

• Started SLD

• Configured SLD connection in the Visual Administrator

I guess the next step would be to tell SLD about the R/3!? Any hints on that?

I read about transaction RZ70, which would require some service patches. However, installing these patches is currently not an option for some reasons. So, I hope there's another way?