The button and text box objects can be edited using standard css like in my tutorial here. However, the progress bar and slide bar have elements that don't seem accessible by this method (it seems better to use sprites in those cases).
Did you have a look at the capx that comes with the tutorial? It's all in the big loop that captured the date from the CSS data string. You might be trying to do something that isn't supported - you can only CSS certain objects.