Is there a special mortar I should use to mount a meterbox?

I'll be upgrading my bays to accept credit cards this year. The current meterboxes are very nicely set in to the brickwork and looks like a bead of mortar goes all around them, just like a brick. I'll have to cut in to the adjacent bricks to put in the credit card box and would like someone's advice on two things.

1. What type of saw, or tool combination should I use to cut out the current bricks/mortar?

2. When mounting the credit card box, is there a special mortar I should use to set it in? Also, is this enough to hold the box in or should I tie it to the current meter box or surrounding brick?

Your experiences with this would be appreciated!

If the reader is in a box, mount it to the meter box and just match the mortar color. The only reason to seek special motor is if they use special median(sand or pebbles). Most likely it is just sand, match mortar.