I have 2 Ironports in my cluster, each in a different locations.  What I did was create 2 seperate connectors, each with a different cost that way if one connector is not available the other connector will work.  Exchange uses the connector IP addres...

I use it on ASA5505 and it has found loggers on user's home PCs. It give us the extra "feel-good" factor of making sure user's home PC is clean.