yupp, both beads need to be broken, but only one side of the tire needs to come off........ try a dealer or shop. they should have them considering thats what they do.
cut the old stem out.
do the board method for bead breaking. very simple. just place a 2x4 up the side wall of the tire and slowly roll up it while someone stands on the opposite side of tire.
once both sides are broken, pull the side furthest to the stem over the lip with some screwdrivers. push the tire over to that side while leaving the one side on the rim.
no you have easy access to the stem. push the new stem in- very easy but requires some elbowgrease. pull the tire back on the rim.
soap the beads up and fill em with air. once you ehar the "pop" your all set!
hope that helped..... if you have any questions or need particular in depth info just pm or im me.
-ant