HTTP printing?
Do you mean you know the IP address of the printer and you want to add that?
Am I really that far out of the loop that I've never even heard of HTTP printing?
To add the IP address (port in your post? I dont know) just go to add printer, make it a local printer and do not let it automatically detect it.
On the bottom of the next screen it'll have a drop down list, you want to add a TCP/IP port. Hit next, type the printer IP address, pick the printer type and install the driver and you're off and running.