Notes on creating EDI schemas for BizTalk Server 2004

Originally BizTalk Server 2004 has the limitation of adding new EDI schemas. However SP1 now allows to add new schemas and the KB article 840113 describes how to implement EDI schemas for BizTalk. I had implemented new EDI schemas with the KB article. But I realized right away that some information is missing.
I summarized some additional information which the KB article doesn’t mention. I hope this would be helpful to someone who wants to implement EDI schemas, especially EDIFACT schemas.