Some important likes Related to WCF adapter – BizTalk

Flat File support is provided for flexibility (e.g. backward compatibility, weak type support). This should be described in links below:
Sending IDOCs
http://msdn.microsoft.com/en-us/library/cc185479.aspx

Receiving IDOCs (second link describes additional steps for transaction support)http://msdn.microsoft.com/en-us/library/cc185169.aspxhttp://msdn.microsoft.com/en-us/library/cc185265.aspx

-Sheshu