JQuery :: Cannot Access <input> Element After DOM Manipulation

I built an IE-only function that modifies the DOM to create a custom container with rounded corners and some shading at the top. It only gets called when the browser is IE and its version is < 9. It takes the following block:

And turns it into this:

The UI looks identical to FF, which uses the CSS3 attributes to create the rounded box. HOWEVER, in IE8, I can no longer access the embedded <input> element (which does not change). I'm trying to get the value of the <input> tag with the ID of "username" by doing this:

When I disable my DOM manipulation code so that in IE, it remains an ugly, square box, I can get the value of the <input> element with no problem. Once I manipulate the DOM, IE always returns the empty string while FF and Opera work perfectly.