Can't install Ubuntu 12.04 64-bit on a dual-drive MacBook Pro 8,2

view story

http://askubuntu.com – Good afternoon, this is the first time I participate here as I'm new to Linux. I've been trying to solve the following problem for over a week without any sign of success so I hope there's a much more knowledgeable person here that can give me a solution. I have an early 2011 MacBook Pro (8,2) with Mac OS X running in a SSD. Then, instead of the Optical bay, I have a HDD in where I would like to install Ubuntu to run it natively. I've tried to do the normal installation process, with or without rEFIt, but it seems the problem resides on the communication between the device containing the Ubun (HowTos)