To display the shopping cart box on my right column, *ONLY* on the shopping cart page, I have made the following code edits:

In includes/modules/sideboxes/my_template/shopping_cart.php, I have the following code edit:

case (SHOW_SHOPPING_CART_BOX_STATUS == '0'):
//$show_shopping_cart_box = true;
if ($this_is_shopping_cart) {
$show_shopping_cart_box = true;
} else {
$show_shopping_cart_box = false;
}

In my admin under Configuration > Layout Settings > Shopping Cart Box Status set to '0'.

And in my tpl_main_page.php,

if (in_array($current_page_base,explode(",",'contact_us,shopping_cart')) ) {
$flag_disable_right = false;
$flag_disable_left = true;//added code
}

But yet, *ONLY* the center column displays. Can anyone show me what I'm doing wrong.