Problem creating logical RAID drives using REST / iLOrest tool

Hey all - looking for an assist. If I'm in the wrong place, please redirect me.

I'm trying to use the iLOrest RESTfulInterface Tool to create some logical drives. I have to replicate this across 50 servers, so I'm trying to script it up. I connected into the server I'm using a s a test (DL360 Gen10, fully patched, iLO5), and I can retrieve all the SmartArray info, drive info, etc. Then I'm trying to create a simple RAID1 mirror of two SSDs for the OS, and another RAID1 mirror of two more SSDs for Data. I'm using these commands:

createlogicaldrive customdrive Raid1 1,2 --name=OS --controller=1

createlogicaldrive customdrive Raid1 3,4 --name=Data --controller=1

So far so good... except when I execute either command, I get the following response:

The property you are trying to change has been updated. Please check entry again  before manipulating it.

And nothing happens on the server. (The DeleteLogicalDrive command works just fine, but not the CreateLogicalDrive command.)

Any ideas? I'd even be open to other methods to script this up, and totally abandon this tool if there's a better route....

Thanks!

Mike