How to customize the showcategories shortcode

I was able find a temprary fix. Its not ideal because I had to change the core code. Hopefully in the future the developers of WPEC can add parameters to [showcategories] shortcode to be like [showcategories =1,2,3]

I changed the file called \wpsc-components\theme-engine-v1\helpers\product.php around line 357

$category_data = get_terms('wpsc_product_category','exclude=100,101&hide_empty=0&parent='.$category_id, OBJECT, 'display');
	$output ='';