I have the same problem as purecobalt:
using MB Custom Post Type extension i can't assign custom taxonomy to custom post type.
My workaround at the moment is:
comment line 21 of plugins\mb-custom-post-type\inc\base\register.php:
//add_action( 'init', array( $this, 'register_post_types' ) );
and add this:
add_filter( 'rwmb_meta_boxes', array( $this, 'register_post_types' ) );
As I noticed the register_post_types function is called after register_meta_boxes.
I'm not sure if this is the right solution, maybe it breaks other things.
Thanks!
