RFC lookup

Hi all,

I want to do an RFC lookup in my message mapping where i need a counter in the receiver filename.

I will be creating the table in the same SAP box as the XI box.

Can sum1 guide me on the steps like:-

1) Do i need to import the RFC?

2)Do i need to create Business systems and Communication channels for that?

3)The udf to call the RFC.

I tried to look at other blogs and forums, but could not find a clear solution. I am working on PI7.0 SP 16.