[Plugin: WooCommerce – excelling eCommerce] Checkout Template

Hello I am using Resposnive theme.
https://www.ads-software.com/extend/themes/responsive

It has the hooks as described here
https://wcdocs.woothemes.com/codex/third-party-custom-theme-compatibility/
Just to proove it.
https://themes.svn.www.ads-software.com/responsive/1.7.9/includes/hooks.php

It does not seem to work on the checkout page.
https://www.grappler.tk/catlovers/kasse/
Why not?

Would it be possible to have a differnt wrapper for this page?
So instead of
<div id="content-woocommerce" class="grid col-620">
have
<div id="content-woocommerce" class="grid col-940">

Thanks

https://www.ads-software.com/extend/plugins/woocommerce/