Proper way to adjust partition size on half-encrypted volume?

Hi all,

I have my HD set up like this currently:

Partition 1: Snow Leopard Unencrypted
Partition 2: Mountain Lion Encrypted with FileVault

I would like to shrink Partition 1. When booted into Lion, I can't adjust the partition size, because it says:

"Disk Utility cannot modify this disk because it contains CoreStorage physical volumes. Use command line diskutil instead."

When booted into Snow Leopard, it pretends to allow the resize, but then informs me that I need a newer version of OSX to resize it (I assume this was triggered by installing Lion with FileVault).

What is the proper way to shrink the first partition without loosing data? I worry about using Parted or another third party app since I have encrypted partitions. (I'm not that familiar with macs)

*edit*
Here is the partition layout. I'm guessing it's showing two disks for some reason because of the encryption on disk0s3, so I'm guessing I need to run "diskutil resizeVolume disk0s2 280G Apple_HFS SnowLeopard 280G"? Is Apple_HFS the right format?

/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.1 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS SnowLeopard 299.8 GB disk0s2
3: Apple_CoreStorage 199.4 GB disk0s3
4: Apple_Boot Recovery HD 650.0 MB disk0s4
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS Data *199.0 GB disk1


Thanks,
Ben

Weaselboy said:

I believe you are going to need to unencrypt the Lion volume to do what you want. Then re-encrypt afterwards.

The encryption creates a logical volume that cannot be resized.

Click to expand...

Really? I'm not trying to resize the encrypted volume..


I'm trying to shrink partition 2 (unencrypted), adding space between 2 and 3. My other question is, there is already 4 partitions on the drive, which I believe is the maximum primary partition count.

Thanks,
Ben

Weaselboy said:

I understand, but I just don't think it will allow you to monkey with partitions with that encrypted logical volume there because of the way partitions are managed with an encrypted volume present.

Click to expand...

OK. I'm in a big debate as to wether I should backup and try the command line or not. I had thought the EFI partition stored any of the required pre-boot materials for the encrypted volume, but don't want to take the chance.

Thanks again,
Ben