iOS 5 - connect to an HTTPS server
- (void)setCredential:(NSURLCredential *)credential forProtectionSpace:(NSURLProtectionSpace *)protectionSpace

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:
       (NSURLAuthenticationChallenge *)challenge {

if ([challenge previousFailureCount] <= maxRetryCount ) {
    NSURLCredential *newCredential =
    [NSURLCredential
     credentialWithUser: userName
     password:password
     persistence:NSURLCredentialPersistenceForSession];

    [[challenge sender]
     useCredential:newCredential
     forAuthenticationChallenge:challenge];

   }
   else
   {
     NSLog(@"Failure count %d",[challenge previousFailureCount]);
   }
}