MacBook Pro :: Lost Volume Control When Headphones Are Plugged In?

When I first bought my MBP (January 2012) I had this problem; plug in headphones, and I lose the ability to control the volume using the keyboard controls.Over the phone, Apple had me do a PRAM reset. After that it only happened sometimes, with a regular reboot solving the problem. It happened again today. I did a PRAM reset again because I'm sick to death of the little ******** issues I have with this MBP. (I've brought it into an Apple store, they kept it for a week and said nothing was wrong with it.)  

The PRAM reset got it working ... then I plugged in the headphones. They still worked while they were plugged in, but when I unplugged them. Gone.BUT, not only are they gone for the MBP's speakers, they're gone for the headphone as well this time. AND, not only are the keyboard volume controls not working now, but the little volume slider at the top of my desktop isn't working either. I did a regular roboot, it solved it, until I plugged in my headphones.  But it gets better, the keyboard buttons work if I'm using my headphones and listening to something on YouTube, but they don't work if I'm listening to iTunes. And that's only the headphones, MBP speakers non-responsive in either case. 

I do get the little pop-up interface that shows you the volume going up and down or if it's muted, it even gives me that little chime everytime I click the buttons, it's just not doing anything except looking pretty. I can control the volume either by using the volume slider in iTunes (or whatever application), as well as by going to System Prefrences, clicking on Sounds, and controlling it using the Output Volume slider.

Info:
MacBook Pro, Mac OS X (10.6.8), 2.8 i7, 8GB RAM