api: adding product to user, how?

Hi all,
I'm using aMember API to create new user accounts, what I'm struggling with is adding a product to such a new account. Hope somebody can help.

This is my code to create new account:
$userrecord = Am_Di::getInstance()->userRecord;
$userrecord->setForInsert( array('email'=>$email, 'name_f'=>$name_f, 'name_l'=>$name_l,
'status'=>1));
$userrecord->generateLogin();
$userrecord->generatePassword();
$userrecord->insert();


thanks,
David

thanks Alex,
I get the following error-message when I try to a use your example from the 'offline' plugin:
"Existing payments count [0] exceeds number of allowed rebills [0]+1, could not add new payment"

This what is written to error log:
Exception Am_Exception_Paysystem
Invoice->addPaymentWithoutAccessPeriod [ application/default/models/Invoice.php : 941 ]
Invoice->addPayment [ /Users/david/yabubble.com/htdocs/dev2.yabubble.com/include/_membership.php : 87 ]Exception Am_Exception_Paysystem
Invoice->addPaymentWithoutAccessPeriod [ application/default/models/Invoice.php : 941 ]
Invoice->addPayment [ /Users/david/yabubble.com/htdocs/dev2.yabubble.com/include/_membership.php : 87 ]

This is my curent code:

PHP:

$di = Am_Di::getInstance();
$userrecord = $di->userRecord;
$userrecord->setForInsert( array('email'=>$email, 'name_f'=>$name_f, 'name_l'=>$name_l,'status'=>1));
$userrecord->generateLogin();
$userrecord->generatePassword();
$userrecord->insert();

$invoice = $di->invoiceRecord;
$invoice->setUser($userrecord);
$invoice->add($di->productTable->load(2)); //product_id of the product that I want to add
$invoice->paysys_id = 'offline';
$invoice->calculate();
$invoice->insert();

$tr = new Am_Paysystem_Transaction_Manual($di->plugins_payment->loadGet('offline'));
$tr->setAmount($invoice->first_total);
$tr->setReceiptId('test');

$invoice->addPayment($tr);

thanks

Code:

Array
(
    [currency] => USD
    [user_id] => 42
    [paysys_id] => offline
    [tax_rate] => 0
    [first_subtotal] => 0
    [first_discount] => 0
    [first_tax] => 0
    [first_shipping] => 0
    [first_total] => 0
    [second_subtotal] => 0
    [second_discount] => 0
    [second_tax] => 0
    [second_shipping] => 0
    [second_total] => 0
    [first_period] => 10y
    [second_period] =>
    [rebill_times] => 0
    [base_currency_multi] => 1
    [_items] => Array
        (
            [0] => Array
                (
                    [invoice_id] =>
                    [item_id] => 2
                    [item_title] => yabubble.com
                    [item_type] => product
                    [item_description] =>
                    [first_price] => 0.00
                    [first_period] => 10y
                    [rebill_times] => 0
                    [second_price] =>
                    [second_period] =>
                    [currency] => USD
                    [no_tax] =>
                    [trial_group] =>
                    [renewal_group] =>
                    [is_tangible] =>
                    [is_countable] =>
                    [billing_plan_id] => 3
                    [billing_plan_data] => a:0:{}
                    [qty] => 1
                    [first_discount] => 0
                    [first_tax] => 0
                    [first_total] => 0
                    [first_shipping] => 0
                    [second_discount] => 0
                    [second_tax] => 0
                    [second_total] => 0
                    [second_shipping] => 0
                )

        )

)

Thanks! this is really great....