How do I create a partition using diskutil command

Question

I've shrunk my original partition and now filevault2 has converted it to corestorage, as follows:
$ diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:          Apple_CoreStorage                         315.3 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
Now Disk Utility tells me it won't create any new partitions, and to use the command line "diskutil". I guess it doesn't work with anything other than HSF or FAT.
But, reading "man diskutil" reveals no command option to add an individual partition. Can someone help .. what is the option to add an additional partition without disturbing the others? As I read it, partitionDisk and splitPartition are both destructive. I see that resizeVolume is non-destruction, but I'm fearful of making any changes to the 4 existing partions, since they're all System partitions.
And, while I'm asking, I also don't see any remove option listed .. maybe mergePartitions, but again, I'd be reluctant to merge something into one of these system partitions for fear of killing it?
regards,
Paul

Answer 1

AFAIK, you have to turn off FV2, restart, and then repartition. But, that's just a WAG.