Question: adapt a USB flash drive to replace DVD ROM Drive for CX7 Navi?

[edgarog]

Is it possible to adapt a USB flash drive to emulate the dvd rom drive in order to get rid of this item? I know there's software that creates a copy of a dvd into an usb so you can use it as a virtual dvd, however what other adaptations have to be made in order to utilize this as a replacement for the original dvd drive for the navigation on a mazda cx7 (2008), reason I am asking is that I have a CX7 Sport without Navi and bought an used head unit, but now I realize that I need this dvd drive which I find it too expensive (no less than 300 dlls), I know I also need a gps antena and some wiring to make it work but I need to find alternatives for this unit, any help will be highly appreciated