get a 2 arm pulley like they use for harmonic balancer removal (except they use 3 arms and are way way bigger) and it will come out easy as hell, ive removed mine about 10-15 times everytime the motor comes in and out so its definately a tool to make it easier, and belting it with a hammer even with the nut on will just damage the nut head and wreck the threads,
those ball joint splitters are bloody useless too ive got one and it didnt work at all.
if u cant understand what tool im talking about then let me know and ill take a pic of it for you
hope it helps mate
*edit* whoops just noticed the post is old, sorry ill leave the info for future reference for anyone else needing the do the job