The way I did it is to look for the three groups of dead paladins that the Elder asks you to find, then you can use that as proof after you've gone back and forth from the Brotherhood's computers to dig up the information on "The Chains that Bind" or whatever. Then you tell the Head Paladin about the 2nd part that says they cant' skip ranks and he'll use that against the Elder. He says it will take a few days for everything to go into effect. I have the evidence and turned it in once to see what happened but reloaded and am still in progress of doing the Elder's mission instead of just cutting it short by getting him replaced.