EDI: SOA vs. XSLT+Lookup

It seems to me that we have two options for handling an EDI transformation task such as sending/receiving a document where supplier account number is different than our internal ship to location code, or some other commonly transformed item.

We can use SOA Composer and the existing Message, or we can customize the message by editing the XSLT file and point it to a lookup table where we maintain the transformed values.

I am not aware of any tools to make SOA Composer user friendly, like an excel import and export. However, I'm also not aware of any tools to make editing the XSLT file user friendly.