blg002 on "Querying custom post types with cat"

Am I missing something. The following returns nothing:

<?php query_posts('post_type=my_custom_post_type&showposts=3&cat=185'); ?>

Yes i have posts categorized that way, and there is the for loop, etc. If i remove the cat argument it displays the posts as normal. Is there something I have to do to get custom post types to make the cat argument in a query_posts work?