I'm not very knowledgeable about WPDM, but the folks who actually know this stuff in and out haven't answered so I will take a stab at it. I believe that you can move all of your existing 2011 SW files into WPDM 2012 when you set it up. Individual files will need to be opened in SW 2012 and then saved into the vault, since SW 2011 can't get access to WPDM 2012. The files that get imported as a batch will convert to SW 2012 when you open them from the vault. You can save that conversion time by running a task that converts them for you overnight.
Dean,
I'm not very knowledgeable about WPDM, but the folks who actually know this stuff in and out haven't answered so I will take a stab at it. I believe that you can move all of your existing 2011 SW files into WPDM 2012 when you set it up. Individual files will need to be opened in SW 2012 and then saved into the vault, since SW 2011 can't get access to WPDM 2012. The files that get imported as a batch will convert to SW 2012 when you open them from the vault. You can save that conversion time by running a task that converts them for you overnight.
Jerry Steiger