that zbrush issue is due to unwelded bodyparts (groups)

easy solution:
open copy of figure in uvmapper. set all to one group. save.  use that in zb

after you have done your morph,  to break it back up into parts, import the uvs from the original and continue as usual

I use SYRinj or PoserFileEditor to insert full body obj morphs. Both are painfully easy

Lyrra