WordPress: Activation Email Customization

functions-login.php

<?php
function change_welcome_mail_loginlink( $welcome_email, $user_id, $password, $meta ) {
	$welcome_email = str_replace( 'LOGINLINK', 'http://www.mysite.com/my/custom/login/url', $welcome_email );
	return $welcome_email;
}
add_filter( 'update_welcome_user_email', 'change_welcome_mail_loginlink', 10, 4 );

functions-newmail.php

<?php
function change_welcome_mail_loginlink( $welcome_email, $user_id, $password, $meta ) {
	return "Welcome to SITE_NAME!\n\nYour account has been activated - yay! You may now log in with the following information:\n\nLogin: USERNAME\nPassword: PASSWORD\n\nWe look forward to your visit at LOGINLINK\n\nYour SITE_NAME Buddies";
}
add_filter( 'update_welcome_user_email', 'change_welcome_mail_loginlink', 10, 4 );

ms-functions.php

<?php
/**
 * Notify a user that her account activation has been successful.
 *
 * Filter 'wpmu_welcome_user_notification' to disable or bypass.
 *
 * Filter 'update_welcome_user_email' and 'update_welcome_user_subject' to
 * modify the content and subject line of the notification email.
 *
 * @since MU
 *
 * @param int $user_id
 * @param string $password
 * @param array $meta Optional. Not used in the default function, but is passed along to hooks for customization.
 * @return bool
 */
function wpmu_welcome_user_notification($user_id, $password, $meta = '') {
	/* ... */

	$welcome_email = apply_filters( 'update_welcome_user_email', $welcome_email, $user_id, $password, $meta);
	$welcome_email = str_replace( 'SITE_NAME', $current_site->site_name, $welcome_email );
	$welcome_email = str_replace( 'USERNAME', $user->user_login, $welcome_email );
	$welcome_email = str_replace( 'PASSWORD', $password, $welcome_email );
	$welcome_email = str_replace( 'LOGINLINK', wp_login_url(), $welcome_email );

	/* ... */
}

Thanx for the code. You know if is possible to change the activation email?, the one that is sent before the welcome email, have this text:

Hi,
You've been invited to join '' at
http://mydomain.com with the role of Editor.
If you do not want to join this site please ignore
this email. This invitation will expire in a few days.

Please click the following link to activate your user account:
http://mydomain.com/wp-activate.php?key=0b1c55b36947988b