Previously, I obtained nice results in working with Fractal Terrain + photoshop, exporting the shaded FT file and then processing it to add cities, forests etc.
There are two problem in this.
The first is that in this way I cannot work much on the shadows from elevation.
The second is that I cannot work on area smaller than, roughly, 1000*1000km, because otherwise the fractal pattern starts being noticeable (cranking up octaves in FT don't work on the fractal function I am using, wilibur ridged multifractal).

One way to solve the two problem could be exporting an heightmap from FT and then working on that. I tried the "standard" process for shading an heightmap in PS, but I did not get pleasant results. So I thought of another option, which would be using the bevel and emboss and shadow effects applied to the mountain layer (similar as in pasis tutorial) using the heightmap as a starting point which in this way could be modified more easily, perhaps also obtaining a more pleasant style.

The only way I could think of doing this would be exporting an heightmap as shades of grey (from white-low to black-high, reverse than the usual), and then converting those shades in a gradient of opacity and/or filling in photoshop. If this is a viable option, my current problem is that I don't know how to do this, or if it is possible at all.

Could anyone help me?