Show items on sale in a certain category

I want to do something like this:

[sale_products per_page=”12″?columns=”3″ orderby=”name” order=”ASC”]

However I want the products to only come from a certain category.

I tried throwing in product_categories number=”102″ but that didn’t work.

I’m inserting this into a wordpress Page. Any way to make it do what I want?

Thanks in advance.