For anyone using this on a Mac, I thought you might benefit from this file I whipped up.
https://dl.dropboxusercontent.com/u/417808/Karabiner/private.xml
If you download the program Karabiner (free) which allows you to change keyboard mapping and load this as the private.xml file, it allows you to use the Page Up/Down keys as System Volume Up/Down and the Insert Key as Play/Pause.
If you download the program Karabiner (free) which allows you to change keyboard mapping and load this as the private.xml file, it allows you to use the Page Up/Down keys as System Volume Up/Down and the Insert Key as Play/Pause.