how to update or create custom post-types

Hi,
want to start using custom post types.
Using an importer now to create new posts with pre-populated info as $mypost
How is the following done with the custom post-types?
To be clear: importing this programatically via php script for 100’s of posts at a time. ;
($mypost is pre-populated array with appropriate values as field info)

wp_insert_post( $my_post ); ??

I understand that I could probably skip the post_meta portions as the custom post would have those built in… but I cannot undersand how to do an
wp_update_custom_post type… I find no reference to this function in the wordpress site.