MS punishes my own modem pool

[Jeff A. Earickson]

Julian,

Here's a puzzle...  Our modem pool (137.146.110.0/24) is
listed on dnsbl.sorbs.net, CBL, t1.bl.reynolds.net.au.  Ok,
good.  But if I use "Spam List = SORBS-DNSBL" in MS, then
all of my modem users get their outbound email tagged with
{Spam?} in the subject line, which really annoys my users
and makes me look like an idiot -- even if they are doing
the right thing and sending their email thru our mail-hub.
How to prevent this, yet still use SORBS, CBL, etc?

Jeff Earickson
Colby College