No Sound From Soundcard, Setting up soundcard on OS X Options

I’m totally new to software instruments/sequencing etc. I’ve just installed a Terratec Phase 28 soundcard in my G4 and intend to create a software based studio set-up, using a Yamaha SY85 as a midi controller keyboard. I’m running OS 10.2.8 (along with OS 9.2 on a separate hard drive). I had a small set back when I received the soundcard. On opening the box I found a note of apology saying there was no mac software on the installation CD (Grrrrrrr!). I then had to download the OS X driver and control panel from the Terratec website. I installed it without any problems and after that, all seemed well....until now.

The soundcard is connected to my external amp/speakers using the analogue outputs and I’ve been trying to test it by playing music in iTunes but so far I haven’t managed to get any sound out of it. I’m not sure whether this is an issue with iTunes, the soundcard settings or OS X - I’d have thought it would be capable of outputting audio from iTunes to external speakers, providing the settings/connections are correct. Maybe this is not the way to test it? I don’t know.

I’ve set the phase 28 as the default audio input/output in ‘system preferences > sound’ but the output volume at the bottom of the panel appears dimmed, at its lowest level - meaning I’m unable to increase the level in any way. It says ‘there are no settings available for the selected device’. The manual for the soundcard or the Terratec website haven’t been much help - there is very little info for OS X systems. I’m wondering whether there is something missing - an additional driver somewhere which I still need to install.

By the way, I don’t yet have a software sequencer installed. To get any sound out of software instruments/plug-ins, do they have to be run through a host sequencer - assigning instruments to the relevant midi track etc. or can I play them via midi as stand alone instruments?

Can anyone help me!?