A Brother HL6050D with duplex unit is configured to not use duplex printing as the default. Changing the option on Windows XP to print duplex nothing changes, the job is printed single side.
The opposite is also there: if the printer is configure to use duplex as the default, all output from Windows clients are printed with duplex, independently of its setting in the Windows print dialog. This is true for normal users and print admin users.
From a Linux client there is no problem, I can override the default on each print job.
I installed this printer first under Ubuntu Linux Hoary in August 2005 and this has worked fine. On each print job from Windows the user could change duplex printing on or off. Now a long time never has used duplex printing. Someone want to print duplex and it didn't work any more. In the meantime I use Dapper Drake. Hoary used samba 3.0.10, dapper uses 3.0.22.
This is probably fixed with a newer Samba version. If you still see the error. Please open a new bug with 'debug level = 10' logfiles of the new Samba version 3.5 or 3.6. Thanks!