I use qmail with vpopmail as mail-server.
vpopmaild can be used to change password among other things.
I have attached a driver to use with the password plugin. 'vpopmaild.php'.
It is based on vpoppassd.php!
Also included are the new config.inc.
I added to config.inc this:
$rcmail_config['password_driver'] = 'vpopmaild';
// vpopmaild Driver options
// -----------------------
// The host which changes the password
$rcmail_config['password_vpopmaild_host'] = 'localhost';
// TCP port used for vpopmaild connections
$rcmail_config['password_vpopmaild_port'] = 89;
Please try it out, and commit it to the svn.