Looks like a sliding tee will work with those 2 holes that are opposite from each other in the hub.
How far apart are the two outer holes?
Something like this will work but it only needs to have space for two outer bolts, like was said earlier.
<a href="http://s19.beta.photobucket.com/user/picturedlife/media/00112560_zps87fd906e.jpg.html" target="_blank"><img src="http://i19.photobucket.com/albums/b168/picturedlife/00112560_zps87fd906e.jpg" border="0" alt=" photo 00112560_zps87fd906e.jpg"/></a>