Sorting dhtmlxcalendar column with date and time

I have a dhtmlXGrid that has a read only column of type dhtmlxcalendar. This column has both a date and time value. For example: “Jan 3, 2011 11:47 AM”. I can only get the column to order by date value. How can I get this column to order by both date and time? Below is a code sample of a couple of things I tried.

	    		deployHistoryGrid = new dhtmlXGridObject("historygridbox");
	    		deployHistoryGrid.setDateFormat('%b %e, %y %h:%i %f');

	    			calendar.setDateFormat('%b %e, %y');
	    			calendar.enableTime(true);'%h:%i %f');

You should create custom sorting type … om_sorting