I got my Deskjet 3650 to work by using the OpenPrinting/MacOSX/hpijs drivers.
Go here:
http://www.linuxfoundation.org/en/OpenPrinting/MacOSX/hpijs
Install Ghostscript, then Foomatic-RIP, and then hpijs. Now open the System Preferences, choose printers, and it should know which driver to select. Works like a charm for me.
Sure, it's a lot of trouble to go through, but with this frankly unacceptable level of support from HP, what else are you going to do?
Note: this method works for oodles of other HP printers too. See the full list on the referenced webpage.