disk utility dosnt seem too happy with adding a partition to my existing time machine disk. It has 750GB capacity, with over 200GB avail. i'm just trying to add a 70GB partition and it raises errors every time. i even tried using a mac that dosnt recognize it as a time machine disk, just a usb drive. still no luck. i cant delete the data on this drive, so its important i just resize and partition without deleting. any tips? any other options other than disk utility out there?