We share our printers out from cups using samba. It was working great until a recent update broke the drivers from the windows/samba side. I decided to redo the configuration and use the cups driver for everything. Only problem was that after doing that I couldn't add the third (optional) tray to our HP 2420DN. After reading a little about PPD and using cupsaddsmb to install the cups driver for windows clients, I came up with this hack job that appears to be working.