Do you want to select types of different threshold steps from a symbol catalog or merely turn it on and off? I can do the latter but have no clue about the former. (If I did, I'd add different stair steps to the catalog for selection as well.) Below is an example using a homemade "Basic Stone Block" symbol as a threshold step.
Originally Posted by RPMiller
Dalton "who wishes there was a `solid 5 Bitmap' for lighter depth shading" Spence
I think it would be just as easy to draw the threshold and fill it with the bitmap that I'm using for the floor already. I don't think it needs to be a symbol per se.