How is the hip belt removed? Is it the hex...
How is the hip belt removed? Is it the hex nut found near the ball joint?
Yes, there is a hex bolt located behind the lumbar pad. If you turn the pack over, the "ErgoActive" lettering on the spine will point directly to it. It is a bit fiddly to get to, since you have to pry the padding back to gain access to the bolt. Once you are in there, a 5/32 allen key will do the trick (a key with a 90 degree neck will make this much easier).
Be certain this is what you want before you head out to the mountains. While not impossible, field stripping the hip belt will be significantly more difficult in the elements (cold hands, tiny tools, etc.). Putting it back on will be even trickier. Hope this helps, and enjoy your wonderful, versatile pack!