The bottom padding exists but the content pushes the bottom padding down and is not visible because of overflow:hidden. What you can do is place the content in a container like so:
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
Hello, this is text.
You can play with the fiddle here - http://jsfiddle.net/BMZeS/
Hope this helps.