Make multiple NSURLConnections and using sendAsynchronousRequest:queue:completionHandler: iOS 5 method

I have some difficulties to set up the correct configuration relative to sendAsynchronousRequest:queue:completionHandler: method (NSURLConnection class). My scenario is the following: I set up a singleton class that manages different NSURLConnections. This singleton istance has a NSOperation Queue (called downloadQueue) that makes a request to a web server and retrieves a string path (1). Once