testing supporter plugin


I have installed the supporter plugin and 2 paypal SandBox accounts for seller and buyer.
The transaction goes fine, but the status of teh blogger never goes to supporter and so I can't test the supporter features.
I have tried single and reccurrent payments,
But none of the supporter DB tables get populated.
Do you know if that is a paypal issue, or an issue with the plugin?

To test, I have entered a dummy row in the supporter table, (1, 6, 1263995255), I can now see that the user is a supporter. (6 is a valid blog_id) and the rest seems to be working OK so far