I have several WinXP clients that are connecting to a Win2003 Terminal Server. I've had trouble getting them to map their local printer into the Terminal session.I have tried so many things but only one client can map its printer to terminal session. I have done this things at this article => http://blogs.technet.com/b/askperf/archive/2007/08/24/terminal-server-and-printer-redirection.aspx
Are you getting the event error indicated in that article? Type: Error Event ID: 1111 Description: Driver drivername required for printer printertype is unknown. Contact the administrator to install the driver before you log in again.
That is the usual cause i have seen for this. The driver has to be exactly the same for it to be picked up.
What i have done in the past is to create the printers as local printers on the terminal server and secure them with security groups. This has the benefit of not having to rely on the printer mapping each time. If you are going beyond one or two servers though then the admin overhead starts to cause problems.