I want to add a few partitions temporarily to one of my external HDs. In Disk Utility, my boot drive gets a "+" option to add a partition without erasing, but my other two drives have the option grayed out. Does it have something to do with having leopard installed on the drive? My boot drive and one other have a GUID partition table and another has a Master Boot Record. My third external has Tiger installed and has an Apple Partition Map, I am allowed to click the "+" on this drive as well. So is there a list of prerequisites for the live partitioning?