How to write Checkout Attributes in the Payment Stage of the Checkout Process

I have noticed that the Checkout Attributes are written when the user decides to checkout from the shopping cart. The ShoppingCartController has the ability to write to checkout attributes since it has the checkoutAttributeService. However, in the payment stage of the checkout process (CheckoutController), there is no access to the checkoutAttributeService. Is there any way to allow the writing of Checkout Attributes from within the CheckoutController?


Thanks!