patcunha, if it's a network printer, then you don't need to depend on eBox to print for it, just setup your windows clients to print to a TCP Port with the printer's address. Can you ping the printer's address? Can you telnet the network tcp port (telnet PRINTER_IP 9100)?
Sure, if it's a domain it would be nice to use it with samba to allow your users to see the queue of print jobs and stuff.. If eBox doesn't show up this printer's driver, you can use the ljet4 driver, since this one works perfectly!