unable to create fusion drive with SSD and HDD

Hi:

I have a late 2008 macbook (2.4 GHz), in which I replaced the optical drive with the hybrid 500 g HDD and added the Samsung 840 series SSD (240 g) in the original HDD slot. I am running OS X 10.7.5 on the macbook.

The system shows two drives, but no matter what I try, I am not able to create the fusion drive. I tried booting the system using Command - R (since my boot drive is SSD) and tried the following command in Terminal:

diskutil cs create newdrive disk# (SSD identifier) disk# (HDD identifier)

Every time I try this command, it says the CoreStorage operation started, and then it gives the error "Invalid Request".

Also, "diskutil cs list" command shows that I don't have a corestorage volume on my system.

I tried formatting the hybrid HDD and then tried the fusion, same result. I tried installing the OS on the HDD and then tried fusion, same result.

Any help will be greatly appreciated.

~ paresh