code: public function checkConfigBE( array $attributes )
  	{
  		return array_merge( parent::checkConfigBE( $attributes ), $this->checkConfig( $this->beConfig, $attributes ) );
  	}
docs: Checks the backend configuration attributes for validity.
  
  @param array $attributes Attributes added by the shop owner in the administraton interface
  @return array An array with the attribute keys as key and an error message as values for all attributes that are
  known by the provider but aren't valid