Hi Recher,
Welcome to the site and thanks for posting!
I am not sure if you are trying to print locally or map a printer under an RDP/ICA session.
Try using the JetCert utility to configure the printer and then add the device as a network printer. Remember to specify the print driver names exactly as they appear on a full windows PC. The test print function only send generic text so if this does not work because the printer does not support it try inside a session.
If it is a session printer does it map correctly? I bit more info on what application (IE, RDP, ICA, Terminal Emulation) would be great,
Cheers,
-TT