(keitai-l) Emoji munged in mail transport?

Hi all,

I recently started forwarding my DoCoMo mail through a homebrew proxy 
server, which works great ... problem is that the emoji don't come 
through.  They all get turned into hex 0x22 0x2e characters somewhere 
in the path.

Anybody have experience with losing and recovering emoji with DoCoMo 
mail?  Is it the case that:

- Does DoCoMo simply munge all the emoji when sending to a non-DoCoMo 
destination?
- Is there something on my mail server that prevets me from receiving 
emoji (anti-spam software perhaps, or the configuration of the 
particular MTA)?

The server runs Linux and otherwise handles Shift-JIS encoded mail just 
fine.

Sorry if this is a FAQ ... couldn't find an answer in the archives 
anywhere.

Thanks in advance for any answers or advice!!

Cheers,
Joe