The DMU tab no longer appears on the File New dialog in managed NX2212.
This was an intentional change in NX2212 and is "as designed".
In NX2212, there must be a Design displayed for an assembly before the ability to create "New DMU Workset" is available in the NX session. The DMU template selection tab is presented at that time in the Create Workset dialog.
In NX2212, users now have to open (or create) a file. Then in the menu ribbon go to the 'Assemblies' tab and select the 'New DMU Workset' icon to display the DMU templates.