Yes you can. Follow the procedure below to set up the UltraNova with GarageBand 11.
1) Ensure that you have installed the latest version of the UltraNova Software Package.
2) Connect the Ultranova to you computer.
3) Load GarageBand, select Piano as your first track and then click on 'New Project'.
4) Go to the GarageBand menu and select 'Preferences'.
5) Click on the 'Audio/MIDI tab and select the Ultranova as the Audio Output and the Audio Input.
6) Click on the Track menu and select 'New Track...'.
7) Select 'Real Instrument' then click 'Create'.
8) Click on the track menu again and select 'Enable Multitrack Recording'.
9) Select your Piano track and click on the 'Edit' tab on the far right-hand side.
10) Click on one of the Effects boxes and select the Ultranova Editor.
11) Turn the volume down on the Piano track.
12) Click on your Audio track and select the 'Browse' tab on the far right-hand side.
13) Select 'Stereo 1/2 (Ultranova)' from the 'Input Source' menu. Set the Monitor menu beneath to 'On'.
14) Ensure that on each track the record enable buttons are switched on.
15) Turn the 'MONITOR' knob on the Ultranova all the way to the left so that you are monitoring 'FROM HOST' only.
16) Play some keys on the Ultranova whilst watching the level meters on your Audio track to check that the signal is being detected by GarageBand.
17) Press record.
18) If you would like to use the Ultranova editor to edit the sound click on the Piano track, followed by the 'Edit' tab on the far right-hand side. Click on the image next to the the Ultranova Editor to open it.