I do have my results page setup to search based on an item or category id, and it's configured with the DataAssist Search server behavior and setup to search the id column or category column from your products table.
I used the DataAssist wizard, I'm just not sure how add parameters to the links in the menu to have it display the results for that item or category.
I've looked through the support files, but I'll try again. If I don't get anywhere I'll post again.