I actually got the RAW to work in Merge to HDR with multiple conversions of the same RAW file. You just have to finesse it a little, or simply "trick" PS into thinking you took the picture multiple times. To do it, I did three conversions, one at -2.0, 0.0 and 2.0. Then I applied a slight curve on each of them. The reason I did this is so that when PS does an analysis on the photos, it doesn't find a direct correlation among the photos if we did just a straight exposure compensation. Then the next step was to save the photos in a format where EXIF isn't stored like PNG. Then I did the Merge to HDR feature. It comes up with a dialog box asking for the exposure values. I plugged in F2.8, 1/400, and ISO 200 for the EC 0.0 one and 1/100 and 1/1600 for the EC -2.0 and 2.0 ones. Then it did its thing and merged them. All that was left to do was to drop from 32 bit to 8 bit mode. I used the Exposure Compensation and Gamma setting with values of -4.5 and 0.6. Then I did a little local contrast enhancement to bring it out a little.