HP Deskjet 3620 via print server

I'm experiencing a weird behaviour of a DJ3620 (USB) printer. If it's connected to the computer's USB port it's working fine. However if I connect it through a USB print server (Hawking Tech PS12U) -and obviously select the proper port-the printout looks like a major cartridge misalignment (about 1/4" on the vertical). Aligning when connected to the print server isn't possible as the applet generates an error ("operation couln't be performed because the computer has lost communication with the device"). It appears that the driver is looking for the printer only on the local USB ports instead of the printing port selected in the printer properties. Any idea how to fix this?