Windows and GnuPG

[Matthew Cordes]

Some people I write to complain that they recieve messages from me that
appear to have two attachments (or perhaps parts) one is the actual message
while the other is a *.dat file (GnuPG signing information).  Both people
use a combination of Pegasus Mail and/or Outlook Express.  Is it typical of
Windows email clients to do strange things like this?  I've tried it myself
with outlook express and it does infact claim a GnuPG message has two parts,
both of which it cannot identify, but I am given the option to open.  The
*.txt file is the message while the *.dat is the hash.

Does this always happen with GnuPG?  PGP?  Is it the fault of Outlook
Express (and perhaps Pegasus Mail)?  Can I do anything to ensure that people
who recieve messages from me receive the message as a I intended?

Thanks Alot,
-Matt