That sucks, there must be a way, rooted deep within the registery, some tiny digit that has to be altered enableing you to add things to the navigation pane
After some looking, it appears epurple is right. Otherwise, I'd check out the customization part of the site. The guys over there know how to do stuff I never even dreamed of before.
It's no help, just a by-gone fact; this was possible in Vista, I used to 'play' around with it but with the addition of Library's that function has been lost.