BC adapter as sender

Hi all

I am working on Scenario BC 4.7 to XI 3.0

In this scnario I am posting IDoc from R/3 system to BC server and then BC system will route tht IDoc-XML to XI system and thn I am sending tht Idoc Xml to FTP

I configured BC adapter as sender on XI side .

What are the setting I have to do on BC side and XI side to configure BC adapter as sender ?and How the service in BC will trigger this event?

Thanks in advance