Product Data Options missing. Add to cart appearing on OOS items.

I've just been asked to manage an EShop installation. I've been looking at the documentation (RTFM) and there's a whole load of Product Data options that are missing in my installation, the Stock Checkout option being one.
Does this need enabling somewhere?

A supplementary question; at the moment Add to Cart is still available on OOS items can this be turned off anywhere?

It seems a little counter-intuitive to wait until you get to the cart before the message "so that it's not until you look at the cart that you get the message "Products marked *** are..."

Many thanks for any help.

If I am reading this correctly you want the following behavior:

1. Products with 0 quantity cannot be purchased by customers.

Is this correct?