BuddyPress.org

Hi,
I created a new custom field in Buddy Press : classement
I would order my list member on this custom field
I understood that I can add a new order type with :

function custom_add_members_directory_order_options() {
	?>
	<option value="rang"><?php _e( 'Par rang', 'willy-bp-custom' ); ?></option>
	<?php
}
add_action( 'bp_members_directory_order_options', 'custom_add_members_directory_order_options' );

And ordering with this :

add_action( 'bp_pre_user_query', 'custom_pre_user_query', 10, 1 );
function custom_pre_user_query( $user_query = null ) {
	global $wpdb;
$user_query->uid_clauses['orderby'] = 'ORDER BY classement'; // Here is my new fields
	$user_query->uid_clauses['order']   = 'DESC';
}

But I’m not sur hat the order instruction is correct because the fields’ name isn’t classement is database (cf tables bp_xprofile_date and bp_xprofile_field)
Have you a solution for that please?
Best regards