Shortcode on BBpress forum?

That depends on where exactly you want it displayed. To put it on top of the main content, you can use this in your childs functions.php file

function add_to_forums() {
	if ( ( function_exists('is_bbpress') && is_bbpress() ) && ( function_exists('is_buddypress') && !is_buddypress() ) ) {
			do_shortcode('[yourshortcode]');
	}
}
add_action("kleo_before_main_content", "add_to_forums");

If you want it elsewhere, take a look in the template files located in /kleo/page-parts; specifically the before wrap, title and header files. Look for do_action(‘xxxx’) and change “kleo_before_main_content” in my example to whatever xxxx is.