Admin order details change suptotal including tax

Hi, Im looking for a solution to change the subtotal value in admin order detail page from excl. tax to incl. tax. Already use RD Order Modifier for WooCommerce to achieve having product prices incl. tax. Its really annoying that woocommerce does offer the build in option to display prices incl. tax only on the frontend and not on the backend too. This very confusing for customers when they receive their bill. Maybe someone can help with a snippet?