------- I am unsure if it can even be done ---------
Um, I did say I checked before answering didn't I <g>?
Elmer, yes it can be done but it requires a pretty recent version of TS to do it without addons, and the client should be thoroughly patched as well.
You configure it by redirecting COM ports on the client side. There is an RDP configuration file on the client where this stuff is stored, which looks like plain text (I checked mine) although the option is available through some mgr interface settings.
Here is a KB reference to how to programmatically determine whether such redirection has taken place.
