[exim] sophos puremessage

The University has been looking at commercial products to help fend
off spam; one of the leading contenders was Sophos' PureMessage,
partly because we've been using their AV stuff but mostly because it
looks like a good product. However, when their "sales engineer" came
to talk to us, they said that Exim wasn't supported due to
"performance problems" and that it would never be supported. As PM
seems to be using a milter interface (I say seems for the same reason
I put "sales engineer" in quotes), so having it work with Exim
shouldn't be rocket science...

My question to the masses is, has anyone out there tried getting them
to work together, or talked to Sophos about doing same?

K.