I too am glad it worked.
Router typically hands out the ip addresses, so if your bud set it up, try getting the test print to view the ip, and try adding a 1 or a 254 where the last set of numbers is (eg 192.168.1.x where x is the replaced set), then type that in your browser. If it asks for user\pass try admin for both, Administrator for U and admin for pass, or the previous with password or pass for the password portion. This will let you see the setup of the router. If it is giving out the addresses, you can set the printer static (so ip doesn't change) if you use the jetdirect's MAC address.
MAC is sometimes called Physical Address or Hardware Address. Now it is just Media Access Code. This code will pertain to only your jetdirect, and you may need the netbios (also known as host name) name, to set up a static address. The router will give that address only to the printer. When you set up the printer, you can also use the netbios name instead of the ip address, like this: //netbiosname/
This will search for it as a server or PRINT SERVER location, so the ip does not matter. When setting up for a PC, just use: netbiosname where it says address, along with any domain name attached (mynetbios.myhomenet where myhomenet is the domain name). You need to add the domain name to the mac portion as well.
I'm glad you were able to find a working jetdirect. There are other devices that will work as well. usb to ethernet print servers, wireless ones... ...they take your usb printer and run a COM port output through usb, but gather the packets of data on the other end as a print server. They store the packets until they fill the COM buffer, then output to the printer. Most will work with postscript printers very well. Most HP's use a form of Post Script, and since com and usb are two way for the purpose of finding out what printer you've got, you should also be able to see your printer driver working over networking as well by using a postscript driver (even if it doesn't match perfectly to the HP). Some will auto configure the driver just fine, others will require you to select a generic post-script.