Available now in AVA 5.9
It is now possible to create emboss and deboss layers directly from the 3D Designer window, using your height data.
The 3D Designer Window now features a Heights to Layer button.

Active height layers can be added into the design as either a single emboss layer or two new layers (positive and negative values, where the first would be considered emboss and the second deboss. The user can specify whether the new layers are 8 or 16 bit.

This is great for mixing textures together to create a new emboss layer.