Media button redirection?

Is there a way to redirect the folder buttons on the side of the UI (Documents, Music, Video, etc.) to another place?

For example, I recently installed PortableApps on an external HDD that I use to back up my "My ____" folders on my Desktop.

Instead of pointing to G:\Apps\Documents and G:\Apps\Music (as they do now), it would make my life immeasurably easier if I could direct the buttons in the program to G:\Documents and G:\Music.

Is there a way to accomplish this?