[TYPO3] Templavoila: switching DS/TO on a page

[Rino Razzi]

Hi everybody.

I have a problem about using different DS and TO on the same pagetree.
I'me using typo3 4.1.1 and templavoila extension.
I'm making a double versione web site: one normal version and one 
accessible version.
The default access at the site is to the normal version. There you 
find a link to accessible version.
The accessible version shows the same content the normal version does 
(the pagetree is the same) but using a completely different layout.
So, the accessible version sould use different TS and TO and I have 
made two DS and TO ("Normal [Template]" / "Normal [TO]" and 
"Accessible [Template]"/ "Accessible [TO]" ).
I thought to use a variable in the URL (Let's say "A" for 
"Accessible"), checking the variable with conditions (like this: 
[globalVar = GP:A = 1]) and switching DS and TO defined on the root 
page of the site from "Normal" to "Accessible" or from "Accessible" 
to "Normal".
My problem is here: how do I change DS and TO of a page in 
TypoScript? Is it possible?
Is there a different way to manage my problem?
I have read the "Templavoila" manual, the "Futuristic Template 
Building" tutorial and the "Localization Guide". I searched the 
typo3-english mailing list and the templavoila mailing list but I 
didn't find a solution.

Thanks in advance for your help

Rino Razzi