Headphone Jack as in/out

Hey everyone.

I recently purchased a new 15" Macbook pro, and I have run into a couple of problems regarding recording:

I was trying to record into my headphone jack, as I know that apple includes (Or at least has in the past) the ability to use it as in or out.

While looking for a converter that allowed me to plug in a 1/4" inch cable, I came across this product that splits the headphone jack out into two 1/8" female jacks, one for headphones and one for "mics" or audio in. The headphone side works flawlessly, but I still can't figure out how to set it up so that my computer reads input through the jack.

When I go into my sound preferences while it is plugged in, here is what I see:

Is there anyway to use this port as an audio in? I record into logic mainly, and use bass, guitar, synths, microphones etc. to record with. I have a large tascam unit that has 16 in and out so it isn't 100% necessary for this to work, but it would be an ideal option for mobile recording and simple tracking.

Thanks a lot for any help! haven't been able to specifically solve this so I figured I would ask.