The only version ive seen is for nonIS-IS like that one but for an IS mount on the caliper :? Post mounts are standard now so its just a matter of adding the adaptor to the adaptor.
I think that's the easiest way to do it. Otherwise you'd need different nonIS-Post adaptor for each disc size.
I found some Bombers in the garage with this fitting so hopefully I'll make a start next week.