When it's time to do something with an FT map I usually just zoom into the new area and export the new CC2 file. Saves lots of time and aggravation dealing with multipolies and such.

If the original map didn't have enough fractalization in FT then you can also just up the roughness of the world a trifle and it will increase the fractalization of the CC2 output.

If it's a map that you've done lots of postprocessing on in CCx then I do understand the desire to play with it directly in CCx but I'd still start over again on the new map from FT because FT has a tendency to spit out more line segments than CCx really wants to deal with and fractalizing those down even further can drive the CCx engine to madness sometimes.

Admittedly, I don't do a lot of exports from FT to CCx anymore so things may have gotten better in the newest releases of CC3 but FT still has the same oddities of behavior that it always had.