yes once and it was a non tls, i used forwarding mode.
they changed the cost from 10 to 40 for the barracuda and the NP for email had a cost of 10.
i put in the ip address of the barracuda in the ip address box and disabled mxlookup i believe...
it all worked it was a simple seltup...make sure that opportunistic tls isnt enabledd in exchange.