I added a core router in front of my Edge (that now handle only pppoe connection).
I decided to go with v3 beta7 and at the beginning everything looks ok.
But I soon saw a problem about rtp traffic of my voip customers.
For some strange reason the rtp traffic didn't go to my pstn gateway and back to cusotmers.
But both customers and pstn gateway sent rtp traffic to sip server in a very wired behavior.
The only way to correct this issue is to disable connection tracking on the core beta7 even if no firewaalk rules were enabled.
So with connection tracking disabled everything looked fine.
With connection tracking enabled rtp problem arise.......
At the moment I am back to use just one machine to handle routing and pppoe connections.
I don't understend why a conncetion tracking could lead to this behavior.