Trouble with my Rear Disc Conversion Options

[Coomer]

My rear disc brake conversion is quickly turning into a nightmare. I got the backplate and e-brake components and e-brake cables bolted up and slid the rotors on, only to discover that once I bolt the caliper on it hits the rotor.

When I looked at the back of the rotor, it looks as if the rotor should sit further back, because there's a groove on the rotor where it looks like the backplate should be.

Here are a couple pics:





Am I correct that the rotor should slide back further than it is in those pictures?

I ask because the part with the wheel studs stops the rotor from moving back any further. I'm using the stock part(hub I think it may be called), and the backplate, e-brake components, e-brake, cables, rotors, and calipers are from a 5th gen.

Attached image(s)