iMac Not Finding Interface

I'm new to the whole digital recording thing, so please bear with me. I have a Presonus Firebox interface that I've connected to my iMac (OSX 10.5.4). It's powered up with one of those wall-warts and the blue light on the front indicates all is well. However, the Mac does not recognize the Firebox at all. Any tips as to what may be wrong or something I'm missing?
I've called Presonus and listened to about an hour of bad jazz fusion on hold before giving up on them.

 

Sorry. I didn't see your previous post. I'm having a heck of a time getting this thing to work. Sometimes I can go to the AUDIO/MIDI panel in Utilities and the interface shows up, sometimes it does not. Even when it does, and I change all the audio settings to accept the interface, then I can't hear a thing in Garageband. Totally frustrated here.
Thanks for the advice, by the way.

 

Thanks all. The Presonus Firebox is just not showing up in my audio options. The light is on, but no one's home. It has to be a faulty box. I'm sending it back and hoping for better luck with my next interface. Just getting the gear out of the box, got me all fired up to do some recording so I'm moving forward maybe with another Firebox or a similar firewire interface.

 

Thanks, Nixo. But according to Presonus, it's compatible with Mac and Leopard with no additional drivers or downloads needed. Anything I plug into that firewire port shows up in the hard drive except the Firebox interface so my only conclusion is a bad interface. I wish there were some magic bullet that would get the thing working, but I've searched everywhere and can not find an answer that gets me a fix.