Are you trying to use the Hosted Solution product? The first screen shot makes it look like you are. There are different layouts for the Hosted Solution checkout method but they all have some variation of that landing page first.
The only way to avoid that first page is to use the Express Checkout product on its own without using the Hosted Solution at all. Your buyers would be redirected to the page in the second screen shot right away.
You will get IPN posts when payments are made through the credit card form or the Express Checkout page. PayPal is the gateway for both methods.