AtomAPI: can't post UTF8 feed with international characters

UPDATE: problem solved - I was chasing a red herring here, a side effect of Russian characters caused malformed xml. The LJ ISE is really not helpful here, but it's a different problem. - Thx

I'm trying to post a UTF8 feed that actually has international characters. The server ISEs 500. Works great without international characters. Feed looks like good utf-8 to me. Netmon trace after the cut.

Ideas?

Thx
dB.