Create globally available volume control for iTunes I'd like to change the volume on iTunes from the keyboard at anytime, regardless what app is currently being used.  

I understand there are the keys at the top dedicated for system volume (this won't work for me) and that there are shortcuts within iTunes.  I'd like something similar that is globally available, whether or not iTunes is my current app.

Details on why I want this:

I use an external audio interface/driver/card that disables system volume control for the keyboard buttons, and is instead controlled by a hardware device.  This controls all volume, and I usually have two or three sound sources going - I'd like to have a dedicated control for iTunes... mapped to the system volume buttons would be the best, but any keys will work.
The best resource for anything like this is Doug's AppleScripts, in this case possibly the collection by Wally - Wally's Scripts v1.0 

There is also a simple tutorial on how to make your own - Setting iTunes EQ and Volume with AppleScript

The only extra thing you need is to make these using Automator, as a Service, then use System Prefs > Shortcuts > Services to assign them global hotkeys [making sure to avoid other used key commands]