Message dropping during bounce?

We recently started sending ADTs to a remote server through a VPN connection.  After a few minutes of no activity, their side drops connection. This happens *a lot*.  I set up an alert to automagically bounce the thread after it starts having pending messages.

Now we’re getting reports of missing discharges.  I checked the time stamp of the missing messages (the engine shows they were sent) with the times of the auto bounces.  So far, each of the missing messages falls within the 5 minute window of the autobounce.  Also, I’ve noticed that the count of messages in and out almost never match on this thread.

Now, I’ve noticed before when I’ve bounced a thread, if I have 10 messages pending, and the thread doesn’t start up, after bouncing it shows only 9 messages pending.  I have no idea where the one message went.  Does the engine assume it was sent even though it didn’t get an ACK?

I guess my question is, is the engine tossing a message every time it autobounces the thread?  If so, is there any way to stop that?

We’re running version 5.3 rev 1 on a Windows 2003 box.

Thanks