Updating the ExtendedAttributes for a calendar event

I've put quotes around it, and still no luck

	    	jQuery.telligent.evolution.put({
	            url: jQuery.telligent.evolution.site.getBaseUrl() + 'api.ashx/v2/calendars/events/{id}.json',
	            data: { 
		            'id': response.eventId,
                    '__ExtendedAttributes_PostingStatus': context.status,
		            '__ExtendedAttributes_PostingEndDate': "Test"  //t$(context.inputs.postingEndDate).val()

            	 },
	            success: function(response) {
                    alert('success'+response);
	            }
        });

I would inspect and share the raw HTTP request and response produced by this call to see what's being sent and received.