sharnian:
Spoiler
Show
You need to have cover to count as hiding. If he did not have touchsight, you could use bluff and then make a break for cover, but you couldn't use it to stand in his LoS unnoticed. What you need to do that is Hide in Plain Sight. The easiest way to get it is via the Dark template, which can be obtained for ~22k via an item in the Tome of Magic.