Need some D7000 help

I'm having a brain failure and can't figure out the answer. I haven't any manuals with me. So I need some help. Please.

I have my D7000 setup with the AE-L/AE-F button set to Exposure Lock. Now I normaly Set my exposure by finding a suitable target and pressing the button to lock exposure. Then I find a target and half press the shutter button to set focus. (Single centre point using AF-S). Then, while holding down the shutter button re compose. All is fine. Now my problem is when I setup on a tripod. Easy! Find something to set exposure on. Then the fun begins. I need to lock a focus point and recompose without taking my finger off the shutter button. While the exposure is locked I can keep the shutter button half pressed but then try and twist tripod handles and recompose. Then Study and consider composure and if I need a small change I have to start over.

So any suggestions on how the set exposure, set focus and then recompose all while on a tripod? (I know I can reset the focus point but is there another way that I haven't thought of?)

Thanks.