With the different guidance packages using different versions of the EL I'm very surprised that no one's specified a clear ( and hopefully concise ) way on how to do it.
If you wanted a version of one to supercede an older one, I could see where <bindingRedirect> might be useful, but remember, he ( and now I ) are saying "COEXIST".
In my case. I've got a WCSF application ( which refers to EL 3.1 ) that talks to a BL ( EL 4.1 ) that talks to two different DL's ( one built with the Repository Factory - EL 4.1 ) and the other to the Original DAAB ( 184.108.40.206 ).
Other than GAC'ifying every dependent Assembly, I haven't found a relatively simpler way of segrating assemblies this way
A way of segrating assemblies like this..should not require brain surgery skills to accomplish.