I don't want to point out Apple's articles on this but in disk mode you would have to put your iTunes library in that disk area.
Here's the Apple article on moving the library -> http://support.apple.com/kb/HT4527
You are trying a variation of the External Hard disk method documented there.
I recently purchased a new computer and tried to "enable disc use" to use my Ipod as an external hard drive to move all of my data files as well as my Ipod music files. Everything else worked but only about 70% of my music files transferred. I can plug in / read my Ipod on my new computer but about 30% of my music files are not visible - most are songs that I burned from my own CD's so are NOT ITunes purchases.
Where are the last 30% of my files? How can I find them? How can I move them from my Ipod to my new computer? (I can see/hear them on the physical Ipod but not on the Ipod-drive on the computer) Help???????