mixing different binding libraries with 3rd party libs.

["Matthew Armstrong" <turkeypotpie@...>]

Some third-party libraries I use have lua bindings already created (by the owners or some nice contributor).  They are large enough that I really don't want to do them by hand again myself.  The problem is, these bindings are often created with different binding libraries (luabind/swing/tolua++).  Each binding library expects the userdata's metatable to be in a certain format.  So if a userdata is created in one binding library, it can't be passed into another.  

Has anyone else encountered this problem?  And is there an elegant solution to it?