Ascensi,thanks it's partially fixed my problem,i'm using blender pipeline now,exporting both meshes and than apply detailed mesh as shape key to original.
But still,really looking forward to make this subdivision support character base

It will only smooth geometry in CC4/iClone.  If you want a character to have high resolution to be smoother,  just use regular smooth mesh by subdivision or apply the body as a soft cloth if you want it to be smooth and have skin physics (must manually paint physics maps - almost completely black character with grey areas to define skin/wrinkle/flab movement) softcloth adds extra resolution similar to smooth mesh by subdivision.   If you want your character high resolution first to send to zbrush for painting or sculpting, this is backwards, it's only necessary to increase resolution in Zbrush to paint or sculp and then you generate the maps from Zbrush to change the smoothness or detailed surface shape via displacement map (manual export from Zbrush then import into CC)

If you want to create a permanent high resolution version of your character, send to zbrush, subdivide then send back to CC4 using no other subdivision levels, only the resolution you need your character to have. You would need to set it to cloth upon import. You can then update the full body skin weight using the Foot/Shoes template unless you have a CC4 full body template already.
After that new high resolution body has the skin weights applied, you can hide the original character mesh if you like or delete it, but if you delete it.  I'm not a Reallusion staff member, this is my own knowledge/insight on the matter.