The short answer is no, it is not supported. You can use the bones supplied by BIPED but you can not use the skin. This is due to the specific nature of Character Studio that does not allow a straight forward support of some features like muscle bulge, etc.
Muscle bulges information are used within the Physique modifier. So yes it seems quite hard to export such skinning information. But biped only deal with bone transforms, or am I wrong? Since your last answer, did you have a recent try to export biped, or is it still not planned ? Just to know if we should ask our artist to restart the models using bones.