I have an HP cp1700 with the duplexing unit. Prior to upgrading to 8.04, I was able to double-side print to that printer. I also have an HP Photosmart C7280 that has a duplexing unit and I can double-side print to that printer. My Mac and my Windows boxes can print double-sided to the cp1700. The current cups driver is the CUPS+gutenprint driver. I tried switching to the foomatic driver and got the same results. Any ideas on how to diagnose and/or resolve this problem?

Thanks,
Dave