BuddyPress.org

I’m trying to change the content of the standard message sent by BP when a user registers.
Since the site search is not working properly and I have searched in vain for an answer I’m gonna post the question here.
I have started with this code added to my functions.php of my theme.
function fix_bp_activation_message($message) {
CONTENT
}
add_filter(‘bp_core_activation_signup_user_notification_message’, ‘fix_bp_activation_message’);
What do I place in the CONTENT if I need to place the username, password and a different welcome message along with the activation link for the BP account?

For example I want it to look something like:
Username: USERNAME
Password: PASSWORD
Thanks for registering! To complete the activation of your account please click the following link:
THE BUDDYPRESS ACTIVATION LINK

Wordpress 3.4.2
Buddypress 1.6