Combining HDR merging with panorama

HDR merging with a panorama is just a useful as with a single shot, but C1 can not perform both types of merges simultaneously. Since panoramas are shot on full manual, they could be bracketed as well. This would allow you to produce 3 bracketed panorama DNG files that could be HDR merged, except as the manual says, "Only RAW files from supported cameras can be merged with the HDR merging."

DNG files are equivalent to RAW files. Why can they not be used to do an HDR merge?