Think sideways a little ...
The disk is what 5mm, so get some 6mm thick material or a mil thicker than whatever your rotors thickness is. It doesn't matter what it is as long as it doesn't compress.
Take the caliper off and bleed it with the nipple upwards. Once the airs all gone and it grips your bit of metal, plastic or even wood the brakes been bleed.
Put the caliper back on and give it a pump to take out the extra mil and done.
Usually makes life easier as you don't have to wrestle it round to an odd position on the rotor.
Very odd thing with my S2R is that the back brake works... honest!! It took me by surprise first time I pressed it when rolling as it actually did something... it was almost frightening
