Aside from turning V4's body parts invisible, there are other options that can be attempted.  If the morph(s) don't exist in the outfit, it/they can be transferred through the 'Copy Morph from...' command.  This may automatically conform the outfit to the model or a simple copy and paste will set the parameter dials to match.  Another consideration is the 'Copy Joint Zones from...' command from V4 to the outfit especially if the model is a Weight-map conversion.  

But, it seems that bringing the renders into photoshop has worked quite well for you.