You are correct, you must use Quick Format for partitions >4GB. There are some 64bit Format programs on Aminet which you can use to replace the WB3.1 version.
None of the existing disk tools will work on partitions over 4Gb unless it specifically says so. There is a new version of DiskSalv (4 or later) you can use, although you have to buy it (probably isn`t avail any more)
