I have no idea about the Nokia case, sorry.

I HIGHLY recommend the Case Logic case I mentioned in another thread here. It holds the N800 securely and includes a very strong elastic loop to keep it from slipping out.

Here's how to remove the faceplate to put buttons back in place:

Open the stand. There are 3 very small slots along the front edge of the device that can only be seen with the stand open. At the bottom of each slot you can see a metal clip. These clips are V-shaped with one edge naturally joined to the faceplate and one clipping over a small tab in the slot.

To release the clips, take a small jeweler's screwdriver (or similar) and push the tabs gently back from the edge of the device, while also applying very slight upward pressure. The clip will slip off the tab and move up a tiny amount. Do this to all 3 tabs. NOTE: be VERY careful! This process can warp the faceplate if you're not cautious and in fact I only recommend this if there is no other recourse.

Once the clips are released, the faceplate *should* pop up a little. You may have to pry the front edge up a bit. There are 3 other clips along the top edge of the faceplate BUT they are of a different design. They have slots in them that mate up with plastic tabs on the case. When the bottom edge is freed, the faceplate will "hinge" up and at that point pulling gently forward on the faceplate will release it from the back tabs. From there you can lift it off and see where the buttons are supposed to be attached. Once they are straightened, simply reverse this procedure to replace the faceplate. You may have to pull the V-shaped lower clips out a bit if they were bent during the initial process.

Once the upper slotted clips are back on their tabs, lower the faceplate until all three of the V-shaped clips snap back over their tabs. There should be no springiness in the faceplate if you have done this correctly.