Membership Upgrade Buttons Not Showing

For some reason no buttons are showing on the suscription page once the user has logged in.

You can see it here:

Ive followed the instructions from here, but still doesnt show up.

Did a rsearch and fount that the problem is in line 242 on includes/renew.form.php.
It seems that method_exists($gateway, 'display_upgrade_from_free_button') return false.

Any toughts?