Alternative to Edge Transport Server

My Company will be moving to Exchange 2007 soon and I have a question about alternatives to using the Edge Transport Server.
I was thinking of using a Barracuda Spam Filter 300.
Could this be a viable alternative in filling the role of the Edge Transport Server in the sense of anti-spam/virus/spyware?

If this could work could all incoming emails go through the Barracuda and then into the Hub Transport Server for routing?