I'm afraid you won't be able to bring in Poser clothes via 3DXchange and have them conform to the iClone characters like they do in Poser. The imported items will be props only and won't bend or fold when the character moves.
iClone has its own clothing system called CloneCloth which allows an almost unlimited range of outfits to be created plus there are many CloneCloth content packs already available for purchase from the content store.
You can find out a little more about CloneCloth from this page:
http://www.reallusion.com/iclone/ic_features_sfx.asp
Peter EdwardsForum Moderator
iClone Daily Blog
Thanks again