The getParams method (In Astract_Query) returns a flattened param array and the setParams method requires the original _param form:

    public function getParams($params = array())
    {
        return array_merge($params, $this->_params['join'], $this-
>_params['set'], $this->_params['where'], $this->_params['having']);

    }

    public function setParams(array $params = array())
    {
        $this->_params = $params;
    }

In order to manipulate the params in a Dql event and pass them back to the query we would need another method to get the _params array like:

    public function getRawParams()
    {
      return $this->_params;
    }