First, at the bottom of the DiskAid window, select "Root Folder". I think you need a jailbroken iPhone to access the Root Folder.
Then Navigate to:
private > var > mobile > Applications > (GIBBERISH) > Documents
The GIBBERISH that I've indicated is a folder whose name is bunch of letters and numbers and there's one folder (with a GIBBERISH name) for each of my downloaded apps from the itunes store.
This app folder contains the following items: Documents Folder, Libarary Folder, "NameofApp".app Folder (such as MobileFinder.app folder), iTunes Artwork file, iTunesMetadata.plist file and tmp Folder.
In the MobileFinder Documents folder, it contains all of the folders in the Home folder of MobileFinder (Documents, Movies, Music, Pictures, Sample Files). Adding documents is easy as drag and drop. I did this on a Mac, so it might be slightly different process on a PC.
I'm pretty excited that I've gotten it to work. Hopefully this is helpful to a few other people as well.