microsnakey....have you tried the backup manager?...
Sounds like the backup manager is working fine for external hard drives but not the internal yet.
To connect to the root of your idevice on widows 7 just go to winscp . net/eng/index.php and download winscp. Then find the ip address of your iphone which must be on the same network (wifi) as your computer, then connect to your iphones ip address and login : root and password : alpine and then head over to the private/var directory and dump the files.
Okay so sadly I can confirm that on my external harddrive GTA 4 is not loading....will keep investigating and update.
You can put the .PKG file in /app_home, or on the root of a USB drive. If you want to install.