Can't duplex print in 12.04

[Jim Byrnes]

Fresh install of 12.04.
Samsung CLX-3160FN network printer
On 10.04 this same printer did and still does print duplex just fine.

The print dialog shows the option for duplex printing and selecting it 
shows the normal 3 options. When I select print the printer acts like it 
is going to print.  The light flashes and the led says printing but 
nothing happens.  It stays that way until I turn it off and on. I tried 
to print a pdf and a text file from gedit with the same results.

If I look at it with the browser interface it shows that the job has 
completed. Also the driver it is using is exactly the same version that 
was used in 10.04. Googling and looking on launchpad shows some duplex 
problems but nothing that seems to match what I am seeing.

It's been 2+ years since I setup 10.04 and I don't remember having to do 
anything special to get it to work on 10.04.  Having said that, my 
memory is not what it used to be, so before I file a bug I thought I 
would check here.  Does anyone know if I should be doing anything beyond 
the basic install to get duplex printing to work?

Thanks,  Jim