Custom Post Type Rewrite

I have created a custom post type called “Products” (slug=”products”) and a custom taxonomy called “Product Categories” (slug=”product-categories”).

I want to include the product category in the URL for the single product pages. For example, it should like this:

http://domain.com/products/shoes/nike-air-jordan

I am exporting the code to my functions file and I see the rewrite argument where the product category should be added (see below). However, I don’t know how to query the product category here or if it is possible to do that within this argument.

'rewrite' => array('slug' => 'products', 'with_front' => true),

I’m thinking…

'rewrite' => array('slug' => $productcategory, 'with_front' => true),

$productcategory = ? (This is the part I can’t figure out.)

http://wordpress.org/plugins/custom-post-type-ui/