Layering issues

I’m developing an isometric tile-based engine, just for a learning experience, I’ve just put in a new layer, the objects layer. Just things like trees, bushes, street lights, barrels etc… will be placed on this.

First I had an issue where walking behind objects would show you on them. (if they reach over the tile they’re on), I fixed that.

Now I have another issue, if you walk in front of an idea it looks like it’s on top of you. I can’t think of a good solution for solving this.

The map is a bitmap, and my character is a MovieClip, what methods should I use to fix this?

Live Example: