Restore the Dynamics database either to another SQL instance or to a database with a different name (DYNAMICSOLD). Just make sure you don't overwrite the existing Dynamics database.
You can then copy the following tables from the backup to the live database.
Export the following tables from the DYNAMICS database in the test environment, and then import the tables into the live environment:
SY09000: Task master
SY09100: Role master
SY09200: Alternate or modified form and report ID master
SY10500: Role assignment master
SY10550: DEFAULTUSER task ID assignment master
SY10600: Tasks assignments master
SY10700: Operations assignments master
SY10750: DEFAULTUSER task assignment
SY10800: Alternate or modified form and report ID assignment master
Note If you use Extender:
EXT80500: PT_Extender_Tasks
This is from the FAQ on security (kb 951229)
Hope this helps.