I refer to the previous session on this topic (http://social.technet.microsoft.com/Forums/en-US/winserverTS/thread/0f373301-e652-4e79-8dee-8e4a6d175c72)
I note that this was closed back in 2008 and am not sure if there have been any further advances since then, seeing as 5 years have gone by.
I have a client that uses software that assigns a users default printer in the software's '.ini' file. Every time that they log in to remote desktop, they will be assigned a new session id. Therefore the previous default printer will no longer be valid as their session ID has changed. They can therefore not print to the default printer. The user has to log in to the .ini file and manually change the setting to reflect the updated session id.
Brenton