What I did was subclass the Button class.

You can edit the template code to do what you like

template: new Ext.Template(
    '<table border="0" cellpadding="0" cellspacing="0" class="x-btn-wrap"><tbody><tr>',
    '<td class="x-btn-left"><i> </i></td><td class="x-btn-center x-btn-center-nav"><em unselectable="on"><button class="x-btn-text" type="{1}">{0}</button></em></td><td class="x-btn-right"><i> </i></td>',

include the code in my earlier post in your page after all the ext stuff and them add the style to your page as well it will all work for you.