SEO keywords to Woocommerce product pages

Hello,

I’m using woocommerce plugin in my site. Does anyone know how to add SEO keywords to each product’s page? For example, to this one: http://servicios.club-mba.com/producto/ensayos-kellogg/

I manage to add SEO title and description to the product pages, but not keywords.

Thanks,
rid

http://wordpress.org/extend/plugins/all-in-one-seo-pack/