How can I receive managed properties by using the serach.asmx?

Hey developers,

I try to get search results via javascript by using the "Query" method of the /_vti_bin/search.asmx webservice (I am using spservices). The default fields are in the result, but I have a problem with managed properties. If I modify the Request XML by adding a properties tag with property tags in it the service answers "BAD REQUEST".

When I am using a coreresultswebpart, I get the managed properties I want (So the fields are correctly crawled).

Here is my code example (if I comment the properties tags it works!):

function MySearch(request) {
	var queryText = "<QueryPacket xmlns='urn:Microsoft.Search.Query' Revision='1000'>";
	queryText += "<RowLimit>20</RowLimit>";
	queryText += "<Query>";
	queryText += "<Context>";
	queryText += "<QueryText language='de-DE' type='STRING'>";
	queryText += "ContentType:'SomeContentType' " + request.term;
	queryText += "</QueryText>";
	queryText += "</Context>";
	queryText += "<Range><Count>3</Count></Range>";
	queryText += "<Properties>";
	queryText += "<Property name='mymanagedprop'></Property>";
	queryText += "</Properties>";
	queryText += "</Query>";
	queryText += "</QueryPacket>"; 
	$().SPServices({  
		operation: "Query",  
		queryXml: queryText,
		completefunc: function(xData, Status) { 
			// work with result...
		}
	});
}

How can I receive managed properties by using the serach.asmx?

I tried to use also the GetSearchMetadata operation, but I do not know how to use it correctly.

http://msdn.microsoft.com/de-de/library/websvcsearch.queryservice.getsearchmetadata(v=office.14).aspx

Can anyone help me? That would be really great.

Best regards,

Björn