Custom Buttons for Add to cart and Submit to Paypal

Can you please help me with customizing the Add to cart button, and the checkout button. (I think some documentation would also be good – unless I missed it) I removed Add to Cart button text and the Checkout button text, tried checking/unchecking the custom buttons check box, copied the css code from the cart css to my style.css

`.wp_checkout_button{
background-image: url(‘images/paypal_checkout_EN.png’); /* 145×42 px */`

Nothing works! the buttons are still just text.

P.S. I think the Paypal button should be right under the total not all the way to the left

Thanks

http://wordpress.org/extend/plugins/wp-ultra-simple-paypal-shopping-cart/