well i went ahead and mounted it, everything lines up perfectly, but i put it in p mode and the flash ready light did nto illuminate, so that lead mt to believe that it was not compatable, but i hit the shutter button by mistake when i was pressing it halfway to get the data on the viewfinder and it went off just lovely, works really nice, but since they arent making happen what is su pposed to happen i think its probably safe just to cover the extra pins up with a non conductive material, like masking tape and use it in manual mode, it seems to work really well and i ahve alot of learning to do since this is my first flash and i dont really knwo what all the settings on the flash unit are for, but i didnt want to spend the money for a 580 ex untill i learn the basics. thanks for the help guys, my biggest concern wheni seen this unit was checking the voltage and it seems safe as its right between 5.8 and 6 volts where as my cobra is 250 v. any tips or advice is appreciated!