How to repair power button?

The Nokia 6030 has its power button on its top as part of the back casing.

I have noticed that the button does seem to work/respond very well anymore on a unit. My impression is that its alignment with the contact it presses into may not be correct. Perhaps the button is somewhat warped.

It looks like the button may be removable, but I have not been able to remove the button with decent pressure from under where it appears to be attached.

How can one repair the power button? Can the repair be done without replacement of the back casing itself?