Setting up IP Printing for HP Laserjet 6MP

Hello friends.

I hope somebody can help me out as I have spent hours trying to get this solved.

I have an HP Laserjet 6MP, connected to a HP JetDirect Ex Plus print server, and I would like to setup IP printing on it. (I do not want to use AppleTalk printing)

My setup is as follows:
- A home network running from a wired router.
- Another second router connected to the first one (because all the ports are used up), with DHCP disabled on it, providing four more spare ethernet ports.
- The Jet Direct is connected to one port
- My MacBook Pro (OS X 10.5.7) is also connected to another port

I have tried setting up the printer through OS X, using the 'Add Printer' function in the printing preference, and selecting both 'LPD' and 'HP Jetdirect socket' options. Neither appear to work though and I think I am getting the addressing incorrect.

I am getting stuck is the following:
- Not sure how to check that the IP address I am entering for the print server is correct
- Not sure how to test if the printer / print server is actually being recognised on the network
- Not sure if I've missing anything else along the way...

Any help or guidance would be really really appreciated.

Thanks,
G