I can't remember the version numbers, but either an updated scsi.device from OS3.9 (3.5 as well maybe?), or the IDE-Fix patched version will allow the partition to work. The size reading seems to be a limitation of Workbench, where the free space number wraps around in multiples of 2 or 4GB. Other programs may read it correctly, but it shouldn't matter really. I've never filled a large partition that far, but I'd imagine when you get to less than 2GB remaining free that the reading would be correct as it's no longer wrapped around.
Anyone else confirm this?