ServiceProxy	= function(serviceUrl)
{
	var _I = this;
	this.serviceUrl = serviceUrl;

	// *** Call a wrapped object
	this.invoke = function(method,data,callback,error,bare)
	{
		// *** Convert input data into JSON - REQUIRES Json2.js
		var json = JSON2.stringify(data); 

		// *** The service endpoint URL        
		var url = _I.serviceUrl + method;

		jQuery.ajax
		(
			{ 
				url: url,
				data: json,
				type: "POST",
				processData: false,
				contentType: "application/json",
				timeout: 10000,
				dataType: "text",  // not "json" we'll parse
				success: 
					function(res) 
					{                                    
						if (!callback) return;

						// *** Use json library so we can fix up MS AJAX dates
						var result = JSON2.parse(res);

						// *** Bare message IS result
						if (bare)
						{ callback(result); return; }

						// *** Wrapped message contains top level object node
						// *** strip it off
						for(var property in result)
						{
							callback( result[property] );
							break;
						}                    
					},
				error:  
					function(xhr)
					{
						if (!error) return;
						if (xhr.responseText)
						{
							var err = JSON2.parse(xhr.responseText);
							if (err)
								error(err); 
							else    
								error( { Message: "Unknown server error." })
						}
						return;
					}
			}
		);   
	}
}