Yes you can.
I just tried this on a UC540 in CCA 2.2.6 and successfully change the Voice VLAN from 100 to 2. Although I was doing this in 2.2.6, this should work the same in 2.2.5. (Note: that this WILL cause disruption in your network, so do this during down time.) Make sure you're plugged directly into your UC540.
I'll post a Lab with screenshots on this later, but for now I'll give you the short of it:
Note: If you have an ESW expansion switch installed, the new Voice VLAN information will be configured for you automatically, and all phones attached will also reset, and re-register)
Your UC540 is now configured on your new Voice VLAN.
In the example provided above, the ip source-address remains unchanged. (10.1.1.1 port 2000) I believe the aim was to change the default Voice VLAN ID, and not the ip scheme? I suppose this would make sense if Pat was conforming to an existing voice subnet. However, even If this was the case, the voice subnet and ip source-address can still be defined during the Telephony Setup Wizard.