powermail

I use Powermail in my custom extension, where it is conditionally included. In order to prefill a field I add GET parameter event which I then add to formaction:

plugin.tx_powermail_pi1.formaction.typolink.additionalParams.cObject.40 = TEXT
plugin.tx_powermail_pi1.formaction.typolink.additionalParams.cObject.40.value = &event={GPVar:event}
plugin.tx_powermail_pi1.formaction.typolink.additionalParams.cObject.40.insertData = 1

The problem is that when a captcha is wrongly submitted, I get an error form with Go back button. However, this button doesn't have this event parameter anymore, so when I go back, the field is not prefilled anymore.

In order to fix it, I've added a new conf option "backaction":

plugin.tx_powermail_pi1.backaction = TEXT
plugin.tx_powermail_pi1.backaction {
 typolink.parameter.data = TSFE:id
 typolink.returnLast = url
 typolink.useCacheHash = 1
 typolink.additionalParams.cObject < plugin.tx_powermail_pi1.formaction.typolink.additionalParams.cObject.40
}

and used it in class.tx_powermail_mandatory.php this way:

if (empty($this->conf['backaction.'])) {
            $targetLinkParams = array(
                'returnLast' => 'url',
                'parameter' => $GLOBALS['TSFE']->id,
                'useCacheHash' => 1,
                #'no_cache' => 1
                #'section' =>
            );
            $this->markerArray['###POWERMAIL_TARGET###'] = $this->cObj->typolink('x', $targetLinkParams) . '#c' . $anchorId;
        } else {
            $this->markerArray['###POWERMAIL_TARGET###'] = $this->cObj->cObjGetSingle($this->conf['backaction'], $this->conf['backaction.']);
        }

It would be great to accomodate this in some sort into powermail.