Exchange Server 2003 - deleting internet headers??

[mw...@sola.com.au]

Hi All,
I've been using spam assassin for a year or more and we have just introduced
exchange 2003 to the mix.     for some reason, people that receive internet
mail have anything about spam assassin removed from the internet headers.
surely this isn't one of microsofts usual tricks to stop the open source
software wave?     talk about stooping pretty darn low if it's the case.

anybody got any ideas?

ta
matthew