How do I choose a payment? /Wie kann ich Zahlungsart auswählen ?

[ternes3]

So I've written two files:
ps_xxxxxxx.php
ps_xxxxxxx.cfg.php

The work in joomla 1.5 (virtumart 1.1.9)
Now I have the two files to / otto / administrator / components / com_virtuemart_allinone / plugins / vmpayment
uploaded.

How can I choose now in Virtuemart?