Help

I need to call a RFC residing in a 4.6 SAP system from a 4.7 system.

Here are my questions:

1.Can I just use message interface or should I import RFC interface from 4.6 into XI?

2.Is it required to use the RFC adapter in this case?

3.Should I need to write a code using Jco to call the RFC.

4.Please let me know the place where I can get the step by step procedure of calling RFC's through XI.

Thanks for your help