Modify existing user position in confirm page

hello i want to change display of account in confirm page
i see this

	<div class="span6">

			<?php $position = 'pp-registration-details';?>

			<?php echo $this->loadTemplate('partial_position',compact('plugin_result','position'));?>

		</div>

	</div>

in invoice defaut_confirm but where i can find to change form for subscription (i want to add title and move link for existing user on bottom)
see my picture