By default for Personal payment system on successful payment there will be a 'Confirmed by User' status. To set your own status you need to activate Advanced settings. For this:
1) create a file 'payments/success.php' which should contain the following lines
<?
$transaction_id = 'ok';
?>
2) on Edit Payment System page tick off "Is Advanced " checkbook and set Advanced Library as
./payments/success.php
3) specify something for Advanced URL (it could be any value, for example 'test')
4) select your preferred statuses on Success, Pending and Failure