btw.. after several attempts to get my external HDD working with SAK, here's my tip for partitioning with windows (and maybe it's worth adding it to the readme.txt?!)
after trying several partitioning tools from the windows one up to Partition Magic, i finally got around the errors by using EASEUS (freeware) to partition FAT32, one partition, primary. then it worked without any problem.
and for those who wonder, to merge the parts back together open your command prompt (RUN-> 'cmd') and from the correct directory enter copy /b Blu-Ray.a? D:\Bluray.iso (or whatever destination path plus any file-name)