Checkout as guest setting name, lastname and email

Question

I am creating a module who comunicates with Visa Checkout. When customer select Visa Checkout on cart I am setting this data:

Mage::getModel('checkout/cart')->getQuote()
            ->setCustomerFirstname($firstname)
            ->setCustomerLastname($lastname)
            ->setCustomerEmail($email)
            ->setCustomerIsGuest(true)
            ->save();

After this I redirect tthe customer to onepage and fill payment data (previously returned from Visa Checkout). I have modified the onepage to don't have billing and shipping information.

But when customer place the order an user is created. How can I disable the customer creation?

Answer 1

I forced this on onepage module (as mentioned on comment):

$this->getOnepage()->saveCheckoutMethod(Mage_Checkout_Model_Type_Onepage::METHOD‌​_GUEST);

And add this on my custom module:

Mage::getModel('checkout/cart')->getQuote()
            ->setCustomerFirstname($firstname)
            ->setCustomerLastname($lastname)
            ->setCustomerEmail($email)
            ->setCheckoutMethod(Mage_Checkout_Model_Type_Onepage::METHOD_GUEST)
            ->setCustomerIsGuest(true)
            ->save();

This solved my problem.