iphone, JSONWriter , object to string

[rashdan]

I want to post a json object to a request. But JSONWriter doesn't seem to convert my object, don't know what I'm doing wrong ...
here's my code for the conversion..

    	customer = [[Customer alloc] init];

	Address *tempAddr = [[Address alloc] init];
	tempAddr.Line1=strAddr1 ;
	tempAddr.Zip =strPost;
	tempAddr.City =strStreet;
	[customer setInvoiceAddress:tempAddr];
	
	customer.FirstName=strFirstName;
	customer.LastName=strLastName;
	customer.CellPhone=strCellPhone;
	customer.Phone=strPhone;
	customer.Email=strEmail;

	SBJsonWriter *writer = [SBJsonWriter alloc];
	NSString *jsonConvertedObj = [writer stringWithObject:customer];
	NSLog(@"the json converted object ... %@", jsonConvertedObj);

Please help. I've no idea what's wrong with the code above.

[iSDK]

<hint> The process is called allocating and initializing.</hint>