If memory serves correctly (that's one BIG 'If'), the recipe Brad wanted a while back is:
1/2 can frozen OJ
1 C milk
1/2 C water
1/4 C sugar
1 t vanilla
ice to fill blender to top
If that tastes not quite right, it may be 1/2 C sugar and 1/4 C water.....
Let me know how it turns out!