I've been very busy for last two months. During that time, I made a converting tool for BizTalk Base EDI Adapter.
Originally, BizTalk Server 2004 had the limitation of adding new EDI schemas. However, BizTalk Server SP1 now allows to add new schemas. This tool generates XML schemas for Base EDI Adapter from some legacy artifacts. To be honest, this tool generates KEDIFACT XML schemas and KEDIFACT is a variation of EDIFACT. I uploaded 41 KEDIFACT schemas of 1911, 1921, 2911, and S93A directories. I guess you also can utilize these schemas for EDIFACT with same directories because KEDIFACT has very similar directories and message types as EDIFACT. I think it requires only small changes. If you have any problem to use them for EDIFACT, feel free to drop your message.