HDR is a broad term, but specifically what it can mean in Vizard is the ability to build a shader that can write to floating point buffers. By that definition, yes, Vizard supports HDR shaders. Vizard R3 also can load .HDR files as texture maps (see below). Currently there are no samples that I can provide you to demonstrate either the shader or texture map functionality.
Code:
image = viz.addtexture('file.hdr')
A good article on the topic of HDR and tone mapping is here:
http://en.wikipedia.org/wiki/High_dynamic_range_imaging
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Regarding depth occlusion maps, I've attached a demo script that shows this functionality. The included depthmap.dlm is built for R3.