In the "and this is why we can't help you" category could we see a image of what it is you are trying to achieve, and the actual CODE that isn't working for you?
Of course, which directions do you want to change dimensions? What type of element are you applying this to? What's the background? You mentioned alpha, is that to show through what's behind your button-type element?
Though I could probably manage what you are trying to accomplish, with it dynamic, with it working all the way back to IE 5.5 USING images, but that's what I do...
But without seeing what you are trying to do, the code that is failing for you, and what type of element you are attempting to apply said styling to... we're pretty much guessing wildly in the dark!