How to get into the secret level?

[SoulHealer]

I have the Wirt leg, the Horadric Cube and a tome of portals, i put the tome and the leg in the Horadric and try to transmute them into a portal for the secrect level, but not works, i hear a sound from my char that says i still cant use it, what is refering to? how do i get that scroll portal for the secret level of the cows?

[DudeMan420]

You must kill diablo/baal first on the difficulty that you want to make/play cows...and if you have beaten the cow king, or gotten credit for killing the cow king you can no longer make.

[trayne]

finish the difficulties then try cow. kill all the cows except king. lure him to a corner and tp out then enter the cow portal again. then you wont have to worry about killing the king.