No, I was hoping, for your sake, that the physical model came from a LDM, because then you could just generate a new PDM using a different DBMS. I don't have any experience doing what you're trying to do, so I can't say for sure what you should do. You might try generating an LDM from the PDM, and then generating a new PDM using the new DBMS. That would take care of the data types and such. You may still have some work to do to tweak the new PDM, though. I'm unfamiliar with your new target DBMS. Good luck to you in your endeavor.
Cheers!
Sean