When you enter the 2nd to highest floor turrrrrn to the right I think? (I don't remember which way you face when you come up those steps. The opposite direction from the obvious staircase anyways.) Then drop down the hole, there's a couple of staircases after the drop leading up to Jasmine.
~You can see the staircases before u drop, so you can make sure its the right hole, there's also a trainer standing right near the staircase you enter, and between you and the hole you need to go down.