Using suffusion, how to intergrate signup form.

I'm managed to get the signup form using the suffusion theme but I'd like it to use a full page, not the default 3 column. Anybody familiar with this theme and how to integrate the signup form without sidebars?

So far I'm just guessing at this:
I am using the sample theme from application/default/themes/sample
Layout.phtml is for the form
Theme.php contains the following code:

Code:

<?php

class Am_Theme_Sample extends Am_Theme
{
    protected $publicWithVars = array(
        'css/theme.css',
    );
    public function initSetupForm(Am_Form_Setup_Theme $form)
    {
        $form->addText('bgcolor')->setLabel('Background Color')->default = '#00e';
    }
}

I'm guessing I need to include that into one of the page- template.php files from suffusion, then copy that hybrid file to theme.php
Am I even a little warm?

Thanks Alex, I have done this but I still can't figure out how to remove the side bars for just the amember pages. What us happening now is that the right sidebar gets forced to the bottom of the amember content and the right side bar space remains blank. Not sure which files are controlling this. So close...

Aha! I just set the default theme to no side bars and now it works GREAT! just need to specify right sidebar for all other pages. Thanks!