Where to override #prefs in mainResponder

[Bill Humphries]

I'm in the process of moving an existing system from the web scripting 
framework to mainResponder.

In the previous framework, an elaborate responder looked at the 
requested URL and 'did the right thing' with it where the right thing 
might be choosing the renderer to use.

What I'd like to do in mainResponder is use searchArgs to override 
values in #prefs when needed.
Now, from my understanding of the website and mainResponder frameworks, 
it would appear that the place to do that would be in 
#filters.pageFilter.

So I would think the obvious code for that would be:

if string.URLdecode(adrPageTable^.searchArgs) == "preview"
{
	adrPageTable^.renderOutlineWith = "previewRenderer"
}

However, that's not working, and the outline is still rendered using the 
renderer to which   #prefs.renderOutlineWith points.

There's also a related question.

According to Userland's documentation, outlineRenderers get a copy of 
the outline without the page directives. If I want to display those 
directives in a view, then it sounds as if I need to provide a subsitute 
for bodytext in my template.