windows 7 64bit driver for a HP laserjet p4015tn

I am working with an almost brand new hp black and white p4015tn laserjet printer.  It has 3 trays and an envelope feeder attachment for the multipurpose feeder.  It was working well with a windows xp machine, and being shared to another windows xp machine.  Over the weekend I replaced the two xp machines with windows 7 64 bit PCs (they are dell optiplex 790).  I used the microsoft windows 7 driver that was automatically picked up when I connected the USB cable.  The users are reporting that the  envelope feeder and the trays are not functioning properly.

I searched the web, but could not find any driver, specifically built for the p4015tn, and for a windows 7 64bit OS.  Does anyone know if there is a good one out there, that exists, and if so where I can download it?  I could not get the Universal Print Driver to work, or recognize the printer.   Should I be dedicating my time to make that work, or is there a specific driver out there?  If I try more to get the UPD to work does anyone recommend the traditional or dynamic mode?  Does either one function better?

Thank you, in advance, so much for your help!