You may also be able to create some morph target functions, that will allow you more flexibility in customizing your skeletal meshes.
Here’s a workflow created by Darthwilson in UDK, this may help you get started:
http://www.polycount.com/forum/showthread.php?p=1547129
UE 4 Morph Target previewer:
Goodluck, post your findings if you’re successful.