CharacterTranscoder is a BizTalk pipeline component + stream class that can transcode a stream from a configurable source encoding to a configurable target encoding.
The source is now available on github.com. Git takes some time to get used to.
I managed to put something online somehow, which means everybody should be able to :-)
Microsoft also offered a free support case for the FFASM bug and the behavior is already reproduced at their side. Nice!