On my 07 cluster and the 06 cluster I bought, that button is removable. I don't know if the earlier clusters are the same, but I'd imagine it's still removable. You can try this and see if it helps.
If you take the cluster out and take out the bolts holding the gauge face itself, you should be able to move it enough to look behind and see the back of the button, mine has 2 clips that hold it into the hole. If you press both of those in and hold it upside down what is left of the button should come out. To replace it just slide a new button down the hole and it should snap in.
If you take the cluster out and take out the bolts holding the gauge face itself, you should be able to move it enough to look behind and see the back of the button, mine has 2 clips that hold it into the hole. If you press both of those in and hold it upside down what is left of the button should come out. To replace it just slide a new button down the hole and it should snap in.
