new tab and bo activity stream

Thanks paolo,
just to give me a kick in the right direction can you explain where i would put the following code.

This is my add new tab in functions.php

<?php add_filter('geodir_detail_page_tab_list_extend', 'geodir_detail_page_tab_list_extend') ;

function geodir_detail_page_tab_list_extend($tab_array)
{
 	$tab_array['my_new_tab'] = array( 
										'heading_text' =>  __('New Tab',GEODIRECTORY_TEXTDOMAIN),
										'is_active_tab' => false,
										'is_display' =>  apply_filters('geodir_detail_page_tab_is_display', true, 'my_new_tab'),
										'tab_content' => ''
									);
	return $tab_array ;
}
add_action('geodir_after_tab_content' ,'geodir_my_new_tab_content');
function geodir_my_new_tab_content($tab_index)
{
	if($tab_index =='my_new_tab')
	{
		echo "Hello world!!";
	}
}
?>

where would i add the following basic activity loop?

<?php if ( bp_has_activities( bp_ajax_querystring( 'activity' ) ) ) : ?>
    <?php while ( bp_activities() ) : bp_the_activity(); ?>
 
        <?php locate_template( array( 'activity/entry.php' ), true, false ); ?>
 
    <?php endwhile; ?>
<?php endif; ?>

Thanks

I am really stuck with this and i just can’t figure it out,
I dont know how to get the php to display on the tab its self, i just keep getting errors, I even tried to add a simple bit of code to get the user id and i got an error!
I have wasted far to much time on this, say i wanted to add this code the my new tab;

<?php function get_user(){

global $bp;
$username = $bp->loggedin_user->id;
echo $username;
}

get_user(); ?>

how would i add it to the new tab?