Laserjet 1020 via Jetdirect 175x - help needed

Hi, I've have a small Mac network and I'm trying to setup my hp Laserjet 1020 via a USB hp Jetdirect 175x (I know this isn't a very Mac friendly printer).

I followed the advice given in another discussion here (thank you poekim) and with an older hp laserjet 1022 driver I got the printer working fine by connecting the USB directly to the Mac. So I know it can work.

I just can't get the printer to work correctly via ethernet / jetdirect. Using the Printer Setup Utility I select 'HP Jet Direct - Socket' under Protocol and enter the IP address (it confirms the address is a 'Valid and complete address'. However the driver does not appear in the HP list under 'Print Using' and when selecting 'Other' I can't find the 1020 driver in Library/Printer or admin/Library/Printer.

I can log on OK to the Jetdirect's Embedded Web Server via Safari.
I've installed, uninstalled & re-installed and the driver several times but can't seem to find it on the system.
I got my hp Officejet working fine via a Jetdirect.
I'm using a Mac Mini G4 with OS X Server 10.4.

Any help would be appreciated. My OS X knowledge is limited - but I'm always willing to learn !
Thanks in advance.