JQuery :: Difference Between Css() And AddClass() With Vendor Prefixed Attributes

I'm not sure if this is a jQuery issue or an IE9 Preview7 issue, but I'm seeing different behavior with these two methods. I'm trying to apply a scale transform using CSS:

.grow {
-webkit-transform: scale(1.7);
-moz-transform: scale(1.7);
-ms-transform: scale(1.7);
-o-transform: scale(1.7);
transform: scale(1.7);
}

addClass('grow') works fine, but if I try to add the attributes with css({'-ms-transform': 'scale(1.7)'}), it doesn't work. My preference is to use css() since I'm building a plugin and don't want external dependencies.* You can see a repro here: [URL], but it only works as intended (well, the addClass button) in IE9preview7. I'm interested in what jQuery might be doing differently to cause the behavior. I'm also interested in approaches others have used to do scale transforms that have better browser compatibility. I like the css approach so far because it doesn't seem to force the growth of the parent container like it does when I manually change the height and width with jQuery.

* I assume to use addClass, the CSS class has to be in the HTML page or a linked stylesheet. Nowhere to define it in a jQuery plugin, right?