Very easy. Here's one method.
Login to your Account.
Click on Merchant Services
Assuming you previously created a few item buttons.
Click on My Saved Buttons
Pick any previously created Add to Cart item button
On the Action Dropdown box, Click on View Code
At the bottom of the page, Click on Create a View Cart Button
On the next page, select your option choices
Click on Create Button
On the next page you can copy the code.
