Can a hero have two ultimate spells?

i tried giving a hero(thrall) inferno(buttonpos=0,2) and earthquake(3,2) but only earthquake came up at the correct position and inferno was replaced by far sight. I wanted far sight to be replaced with inferno. please help guys. thanks.

Then remove Far Sight! :D

i did try removing the far sight ability but when i tried it out in game an icon with a man figure showed along with "missing tooltip"

You can either have the spell 'spill over' into (1,1) or you could use the trigger 'Unit-Remove Ability' to get rid of far sight when your hero levels up to Inferno.