Here are a few tips I encountered when working on an AS2 and EDI project.
You will want to avoid using an EdiSend on the send side of a 2-way port in which the receive is As2EdiReceive because you will encounter EDI assembler errors where the SOAP messages are being run through the EDI assembler. Make sure to use just the As2Send on the send side of the receive port. The AS2 tutorial at http://technet.microsoft.com/en-us/library/bb245935.aspx mentions creating a 2-way port with As2EdiReceive/As2Send. This is the correct way of doing this.
When developing with EDI and AS2, you will eventually want to create a filter for receiving BizTalk NACKs that you may see with AS2 communications. You can create a send port filter using the filter property EDIInt.IsAs2Http200OKRresponse == true. This way if BizTalk does receive a NACK it will not log it as an error. This is a valuable tip for setting up an BizTalk environment for AS2 communications so that low-level AS2 message errors can be filtered out to a separate folder or location.