Need help on LED TV installation!

For something like this I would post several pictures all around where you are wanting to install it and even hold it in place where you'd like it and have somebody snap a photo. Situations like this for us guys who are visual problem solvers need pictures! :)

I'd use something like this and then use longer screws and spacers at the top mounting ears (if you cannot bend them) to get your 15 degrees of tilt.

You might want to look at all the different sorts of mounting brackets available. You might find a different way to mount it that would be easier and more suitable.

Monoprice makes and sells a huge line of mounting brackets that are reasonably priced and good quality. I had a very unique situation with a folding TV shelf in our old trailer. I was able to find a very flexible, removable mount that solved my issue. Look at them with an open mind and see what comes up.

How about something like this?...

Locking Cantilever Mount from Camping World


Or, this one? (I use this one on the TV in my outside bay. Easy to remove and re-install the TV as needed.) One part mounts to the wall, the other mounts to the TV. Then, the TV just slides down into the mount. You would just have to have enough top clearance to lift the TV out of mount.

Surface mount from Camping World

We used this one in a TT where movment wasn't required. Rock solid and easy to remove or hang.

Phenomenal prices on all types of wall mount brackets. I've purchased several for home and RV in the past.

http://www.monoprice.com/Category?c_id=109&cp_id=10828

If I understand your question correctly, you will need to attach a 2x4 board on each side of the cabinet. Then cut a piece of plywood to cover the existing opening and it will screw into your 2x4s. Attach the TV mount to the plywood before attaching to 2x4s. Leave cut outs in the plywood for attaching TV cables. Hold the TV up to the attached plywood, attach cables and then put TV on mount.