walkthrough path - change in elevation

I'm using revit 2009 - is there any way to spec. a specific height of a key-frame? Individual key-frames don't seem to have their own element properties, or none that i can find. The only chance i can see to spec. a height is before i finish path creation and then that's for the whole path. I've created a walkthrough where the camera tracks around a lower floor, goes up a set of stairs, runs around the second level then comes back down the stairs again. what is frustrating me is that i can't set the height of each individual key-frame...the only way i can seem to achieve different heights of key-frames is to go into an elevation view and manually move each key-frame by clicking it with my mouse and manually moving it up or down. This really sucks as not only is this method difficult to line up the different key-frames on a certain level for a smooth walkthrough, but it's almost impossible to tell which key-frame is which when viewed from the side. EG- if i had the camera go around in a circle (in plan view) with, say, 10 keyframes, then i switch to elevation view, how can i tell which key-frame is on the near-side and which is on the far side? using a 3D view doesn't really help, i can see which point i want to pick but moving them (again manually) won't keep it a dead-straight vertical movement. this is driving me insane...please tell me there's an easier way...

ok, nobody seems to know but i have found a solution staring me in the face. like when you create topography, you can type your elevation into a box on the menu bar before placing each point.

What you are trying to achieve can be done very easily in say something like 3dsmax where you have tool for animation. Like a camera to follow a path and use keyframe, not in Revit.
If you are serious about animation i strongly suggest you get into 3dsmax but if it's only for a limited use there's plenty of workaround in Revit, just not efficient.