header filter help requested - preload=true...

[ProxRocks]

i have a particular ssl-site that "refuses" to let me log out (in half-ssl mode, at least)...

i've noticed that the log out "process" 'jumps through' three URL's, the second of those URL's has a &preload=true appended to the end of the URL string...

i've been unable to construct one myself, does anyone have any advice on a header filter that would redirect/jump any URL ending with &preload=true to &preload=false instead?