Add Custom Fields to Page table

Hi,

Is it possible to add custom fields to the page table?

I have tried this in site.php but it does not work:

PHP:

Am_Di::getInstance()->pageTable->customFields()->add(
            new Am_CustomFieldText(
            'page_name',
            "Page Name URL link",
            "Name to be use in URL.\n".
            "This should be SEO friendly."
            ,array()
            ));

Using V4.2.11

Thank you
Alain