Uh, mount the holding tool to the pulley and try again. You might have it unfrozen, but not loose enough to spin off the pump snout. If the nut is turning and the water pump flange isn't, its either getting looser or it's stripped.

__________________
12 E70 3.5i xDrive
03 E46 330i ZHP
01 E53 3.0i
98 E36 323is
12 Audi A4 Quattro
79 Triumph Spitfire
73 MGB