post_type taxonomy

Hi all

Is it possible to have all my custom post_types to use the same taxonomy?

For example if I want them all to use the default ‘post’ taxonomy I tried to use the register_taxonomy and ‘category’, ‘post, but that seems to fail?

So, do custom post_types have to have unique taxonomies? Does it make any sense to build up more then one taxonomy-tree? One for each post_type, or do I doing something wrong?

regards // johannes