Taking into account that the caliper is ok, you need to prime the master cylinder with fluid on "the other side", my mate is having the same problems ATM and I must admit, mine took a while to bleed my brakes on the xs.
It helps if you have a 3rd hand, get someone to pull the lever whilst opening the bleed screw and shutting off before the lever returns. I have also had to suck the fluid through using a clear pipe so as not to drink the stuff
drewps