Computer is unable to detect HDD in optical bay enclosure

Hi there!

I’m trying to install a SSD into my Macbook Pro (15” Unibody early 2011), but I’m having some issues. My goal is to use both the new SSD and my old HDD and make a fusion between the two to be able to use both the space and the speed.

The SSD is an 'INTEL 530 SERIES 2.5" 120GB SSD SATA/600 MLC BULK’.

I bought an iFixit upgrade pack with an optical bay enclosure, and first I put the SSD into the optical bay and replaced the optical drive with it. The computer didn’t find the SSD at all.

I then replaced the old HDD with the SSD and put the HDD in the optical bay instead, and was now possible to find the SSD, format it and install OS X without any problems. BUT the computer won’t find the HDD in the optical bay enclosure either. The only hard drive I’m able to find in Disk Utility is the new SSD.

I’ve followed every step in this guide:

Installing MacBook Pro 15" Unibody Early 2011 Dual Hard Drive

Any suggestions to what the problem might be?

Thanks a million!