[bedoig]

A hard reset will not erase anything stored on the 4GB of internal storage. It is treated in the same manner as a storage card, except that it's not removable.

Edit: To make it a little clearer (hopefully), the Diamond has XX amount of RAM, XX amount of ROM space, plus 4GB of internal storage. I say XX only because there is the possibility that it will change in CDMA form. For all intents and purposes, the 4GB is an unremovable storage card. It is just labeled as "Internal Storage" within WM.