[Infinity101]

The next idea would be to edit the register.php. In the same snippet of code, remove:

if ($profilefield['required'] == 2)
		{
			// not required to be filled in but still show
			$profile_variable =& $customfields_other;
		}

So instead it shows:

if ($profilefield['required'] != 2)
{
if ($profilefield['form'])
			{
				$profile_variable =& $customfields_option;
			}
			else
			{
				$profile_variable =& $customfields_profile;
			}
}