On-Sale products within shop pages

I want to be able to show all on-sale products within my shop, and then allow users to filter products by attribute and/or category.

The problem I’m having is this: the only way I can find to show on-sale products is to use the ‘WooCommerce On-Sale widget’ within a page/sidebar – but this means that the layered nav functionality does not work (because, as I understand it, it only works within the loop on product archives, i.e. within the shop, and not on standard pages).

Am I missing something obvious here? I would have thought that it’s a pretty common requirement to show on-sale products within the store itself, without doing something manual like adding all sale products to a separate product category etc.

thanks in advance for any assistance

http://wordpress.org/plugins/woocommerce/