Problem with installing a full quarter

I am working on my 68 dart installing a full passenger side quarter panel from AMD. Every thing is cut away all the surfaces have treated with Eastwood rust converter. What the problem is that there is a bracket that holds the curved part of the quarter in the very corner. The panel has to go over this bracket while at the same time go under the roof. The bracket is right there at the back edge of the quarter window next to the front of the roof pillar.
How do I accomplish this??? Thanks Jeff