Update_Post That is a Custom Post Type

I am hoping to batch update a custom field within a bunch of posts after printing a report, but those posts are all custom post types. Update_posts works just fine with regular posts, but unfortunately even passing the post ID it things the custom posts don’t exist.

I’ve had to build a custom controller to do some taxonomy wizardry, but I was hoping there was a way out of the box to update a custom post type because ugh.

Thanks for any insight!

http://wordpress.org/plugins/json-api/