Topic: Using - Cubase 5 + RME fireface 800 on a MAC OSX Snow Leopard

Using - Cubase 5 + RME fireface 800 on a MAC OSX Snow Leopard
I am having problems with setting up. I cannot record Audio from the Fireface 800. Midi works fine so I think I must have installed the drivers ok?
I get no signal on the transport bar, the mixer or on the track. In Cubase Device settings I set as 'Built in Audio'. In VST Connections I set as 'Built in Audio'. I can now record audio!. To playback I change settings in device Settings and VST Connections to Fireface 800 and can playback recording. Is there something i should do in Cubase to associate each track with a channel number?  I think there is a connection problem - some people have talked about using a firewire hub - is this still recommended.  -  Any suggestions muchos appreciated!