Custom post types and category widget?

Hi!

I managed to add categories and post tags to my custom post types, but the category widget still won’t find them. It only finds the regular posts in those same categories.

How do I get it to fetch the custom posts as well?

For example, if I click on uncategorized it loads a page at …/?cat=1 and displays the regular posts in that category, but not my custom posts (which otherwise work ok).