[TYPO3-shop] Payment GW: 'This' Must be Object!

[Juan Pablo Villaverde]

In a payment extension for tt_products, like payment_DIBS,  I get this 
message:

$this and $this->cObj must be objects!

when I call the payment handlescript. I tried with the original DIBS 
handlescript with the same result.
I need to specify something more than the handlescript to make the "THIS" 
available from the payment class?

The config is ver simple, something like:

plugin.tt_products {

 tpvExt {
 }
 payment >
 payment {
  10 {
   title = TPV
   handleScript = EXT:user_tpv/class/class.usertpv_ttproducts_paymentTpv.php
  }
 }

}

I just found via google a post of people with the same proble, but nobody 
posted a reply: 
http://lists.netfielders.de/pipermail/typo3-ug-spain/2004-October/000401.html

Thanks in advance!

jp