While I’ve never used C4D, the basics are pretty much the same to exporting to just about any other program. I usually use Blender for exporting to for all of my renders, but it should be pretty much the same from most of the other previous programs I’ve used before.
To start with, go to “paint” inside of Sculptris, to create your texture.
You can do this next part before or after you’ve finished painting the texture, but export the OBJ in this area (Not before you let Sculptris do it’s own UV Mapping).
Now, when you’re done with the “texturing/coloring”, near the bottom of the “tools” area, you will see “Show Advanced Tools”.
Hit that area and a few other options will appear. The options that I usually use are “Save Texmap” and “Save Bump”. Those options refer to the color of the texture and any bump mapping that you may have painted onto your model. Hit those, and save to the specific names for that model.
Next you are going to open your specified program and now import the appropriate files. Usually you would start with the OBJ and then add onto it the appropriate files that specify the colors, etc. of the model you are attempting to continue with, in the strengths of the program that you’re using.
Not necessarily certain that the above will help (since I’ve been drinking a lot…lol), but it should be a rough guide to getting what you are wanting done.