Local Printers don't auto map thru remote desktop

- My coworkers and I use WinXP Pro locally and connect via remote desktop to
a WinSrvr2003 Std server. Our RDP settings specify to map local printers
automatically.
- Some of our local printers don't map. These printers don't have a WinSrvr
2003 driver, and are connected to the local PC by USB. (note, other USB
connected printers do map automatically.) I've been able to add these
printers (selecting an alternate driver) and print locally.
- However, every time we logout/login to the server, the printers don't
work. They are still defined on the server list of available printers, but
are assigned to an inactive port. If I reassign to the correct (active) port
on the server, the printer will work fine (for the duration of that login
session).
- I've tried mapping these printers (on the local PC) to multiple ports
including LPT2, COM1 and COM3 (some of these local ports appear on the list
of available ports on the remote server) but this doesn't fix the problem.
** What can I do to configure these printers so that they are properly
connected to the remote server every time I logon?**
Thanks in advance for your help.