I believe this is possible with the included signup-xtra.php script. With this script you can run Custom PHP/HTML at signup and optionally during manual addition and import. You can even create a new database connection. The only problem is that message codes cannot be used - you need to use the provided variables and/or your own PHP code instead. You know.. we may even be able to use message codes with processmsg but it requires a small modification to ListMail to make sure the $userid variable is available with manual signup and import.
To enable signup-xtra.php, move it to the ListMail folder. Some (incomplete) code such as follows should work:
// only run for list 1
if($list=='1'){
// connect to db2
$link2 = mysql_connect...
// get db data
list($data,data2)=mysql_fetch_row(mysql_query("... where email like '$email' or uid = '$uid'",$link2));
echo "<html>
<head></head>
<body>
Hi $email!, you're now a member AND a subscriber! :-)<br>
<br>
member username: $data<br>
member password: $data2<br>
<br>
</body>
</html>";
exit;
}
The exit; call is important, but could mess things up during manual signup/import.. let me know if it's a problem.
Regards