Cannot send Rich Text Messages in Outlook XP over VPN

[Bill Sugas]

When I try to use Outlook XP to connect to my company's
Exchange Server (we use Outlook 2000 at work) over my VPN
tunnel (using proprietary Lucent IPSEC software for
tunnel), I can receive messages, but I cannot send
message - I always get a "Network Problems are Preventing
Connection to the Microsoft Exhange Server" error.

If I send a Plain Text FOrmat message, the message is
delivered with no problem.

If I reply to a message, even if it is in plain text
format, it does not work.

Help!