thanks but I've done this too
$this->Form->fieldImage("submit", $this->_("PaypalPaymentsStandard.buildprocess.submit", true), array('src' => $button_url, 'target' => "_blank") );
and it stays on the page
EDIT:
Correct me if I'm wrong but this seems to be the image ref <img src="paypal_image" alt="pay with paypal"> so if say the code <img src="paypal_image" alt="pay with paypal" onclick="new.window('$post_to')">, is run, new window will open with a wrong reference. At the same time, original window will go to correct paypal_url as defined in $post_to
In other words, the line ==> array('src' => $button_url, with 'target' => "_blank") will not do anything
So if I want a new window during the POST operation, it'll have to be at the point where "FORM" is submitted. May I know which section the target attribute can be included?