[Plugin: Blog Topics For WPMU] With BuddyPress doesn’t work properly

I have little modified the plugin file and added some code which add the select in the sign up form but it doesn’t still work with BuddyPress:

// Add the actions and filters we need to make all this run
add_action('signup_blogform', array(&$cets_wpmubt, 'get_topics_select_signup'));
add_filter('wpmu_new_blog', array(&$cets_wpmubt, 'set_new_blog_topic'), 101);
add_action('bp_after_blog_details_fields', array(&$cets_wpmubt, 'get_topics_select_signup'));
add_action('signup_finished', array(&$cets_wpmubt, 'save_signup_blog_topic'));
add_action('admin_menu', array(&$cets_wpmubt, 'add_submenu'));
add_action('admin_menu', array(&$cets_wpmubt, 'add_siteadmin_page'));
add_action('delete_blog', array(&$cets_wpmubt, 'update_relationships'));