Octane will not save out a background image (backplate), so I'm not sure how much use this feature would be. You would still need to composite the image outside DAZStudio.Btw. any chance of getting a backplate image option ? Perhaps as an option under Octane->Preferences->Background display (If alpha is activated) ? Current options are None, Border, Checkerboard. An option to load ones own image will be great. The other option would be to pick the image from the DAZ->Environment if present. Either way, it will allow to render with a HDRI light but use a different image for the sky / background.
Paul