Just wondering how I would setup a TS 2003 server for remote access I.E. reverse proxy through TMG to the server via a URL with the usual ports opened

e.g. ServerTS works fine internally and if using my RD gateway works fine externally as all you do is config the connect to use the RD Gateway first then all you have to type is ServerTS in the connection box but I would like to publish this one directly so ServerTS.<schoolname>.<county>.sch.uk and connect via RDP that way?