OS X won't see UC-33

I'm newbie to the forum and Reaper. It's great so far, but I'm trying to use the Evolution UC-33 to control the mixer. I have used this control surface with Tracktion 3 on my MacBook with no problem. I'm using the USB cable to power up the UC-33. I've read the user manual and still am lost. Anyone have an answer. Thanks in advance.

Success! 

Guys, I solved the problem myself, so I'm posting for others who might have the same problem in the future. Here's how it work. Plug in the UC-33 to USB on the Mac, then look in your Utilities folder for the Audio MIDI Setup (AMS). Open it and click on MIDI Devices tab. You should see the UC-33. Open Reaper, load your audio project and click Options tab. Select Preferences/Audio/MIDI Devices. You should see Port 1 and Port 2 on MIDI inputs. Double click on Port 1 to the Configure MIDI Input. Check "Enable input for control messages". Click OK. In the MIDI Hardware settings screen, Click APPLY button and OK button. Select ACTIONS tab. Click "Show Actions List". From the Actions List, highlight "Track:Set volume for track 01 (midi cc only)" then click ADD button. Keyboard or MIDI input box will appear. Move Fader number 1 on the UC-33. Shortcut will change to "MIDI Chan 16 CC 105". Be sure MIDI CC is set to Absolute. Click OK. Close Actions window.Fader 1 now will move the volume on track 1. Repeat for all other tracks. I was able to assign the rotary pots above the faders to pan the track also. This certainly was a learning experience. I hope this info help someone out there. I'll be digging into more deeply in the next couple of days. Happy recording!