The7 add custom post types to microsite metaboxes

functions.php

function dt_add_CPT_to_microsite_metabox() {

	global $DT_META_BOXES;

	if ( $DT_META_BOXES ) {
        foreach($DT_META_BOXES  as $id => $metabox) {
	        if ( isset( $metabox['id'] ) && ( $metabox['id'] == 'dt_page_box-microsite' ) ||  ( $metabox['id'] == 'dt_page_box-microsite_logo' ) ) {
		        $DT_META_BOXES[$id]['pages'][] = 'my_custom_postytype';
		        break;
	        }
        }
	}
}

add_action( 'admin_init', 'dt_add_CPT_to_microsite_metabox', 30 );