Hi.
Maybe this could be usefull:
1. Find and open module.js in <root>/user/selector/
2. Find line 57. and edit it (<label> to <button>) like this:
From:
this.searchfield.insert(Y.Node.create('<label for="'+this.name + '_searchtext">'+searchbutton.get('value')+'</label>'), this.searchfield);
To:
this.searchfield.insert(Y.Node.create('<button for="'+this.name + '_searchtext">'+searchbutton.get('value')+'</button>'), this.searchfield);
Also u can do another way and comment out 58. line ( //searchbutton.remove(); )
This gives back a search button that u can use in IE. Hope it will work for you too