unable to theme cart/checkout table when user can see prices w/o vat

the line return theme_cart_review_table makes it impossible to theme the table with own theme function when user can see prices VAT excluded

/**
 * Theme registry callback override for the cart_review_table.
 */
function uc_vat_cart_review_table($show_subtotal = TRUE) {
  // Using a call to theme() so the new review table can be themed if necessary
  if (uc_vat_exclude_vat()) {
    return theme_cart_review_table($show_subtotal);
  }
  else {
    return theme('uc_vat_cart_review_table', $show_subtotal);
  }
}