Target Conversion to Account

Hello,
I’m trying to modify the “Convert Target” Action in order to convert it to an Account instead of a Lead. I am following this post
I have created custom\modules\Accounts\controller.php

class AccountsController extends SugarController{
	function AccountsController(){
		parent::SugarController();
	}
	function pre_editview(){
		//IF we have a prospect id  convert it to an account
		if (empty($this->bean->id) && !empty($_REQUEST['return_module']) &&$_REQUEST['return_module'] == 'Prospects' ) {
			
			$prospect=new Prospect();
			$prospect->retrieve($_REQUEST['return_id']);
			foreach($prospect->field_defs as $key=>$value)
			{
				if ($key == 'id' or $key=='deleted' )continue;
				if (isset($this->bean->field_defs[$key])) {
					$this->bean->$key = $prospect->$key;
				}
			}
			$_POST['is_converted']=true;
		}
		return true;	
	}
	function action_editview(){
		$this->view = 'edit';
		return true;
	}


}

I am wondering where, in the built in conversion to a lead, the id of the new Lead is set/map in the lead_id field of the Target and how it is then used to show on the lead’s detail view the link “Converted Leadt: lead_id”

Can anybody help me?

thanks in advanced

Rossella