Google Checkout not appearing in payment options

Hi,

I just enabled google checkout on my site and it is not appearing as a payment option when I click checkout from the main page. I just get the message "No payment methods available".

I do get the google checkout button if I click through to the shopping cart though, just not if I click checkout.

Have I missed something?

Matt

Google Checkout is "button" payment method. It's displayed on the shopping cart page.