I've tried several times but can't get it to work. I have a 27" iMac (2011) that has a 1 TB HDD as well as a 120 GB internal SSD installed from OWC. Trying to make a Fusion Drive out of them but keep getting stuck so I'm turning to you all for help! I've been able to successfully "fuse" the drives together with Terminal Disk Utility, but every time I try to reinstall Mountain Lion I get an error message. I have it hooked up in target disk mode to another Mac in Recovery mode. Can't use recovery mode on iMac itself because it tries to restore Lion which doesn't recognize the Fusion Drive. Just need to reinstall Mountain Lion!