MCoeControlObserver not observing CAknMultiLineDataQueryDial

I'm trying to run a CAknMultiLineDataQueryDialog with EEikDialogFlagWait switched off so that when the user makes a selection the dialog disappears and I can show a progress bar as opposed to having to wait for the operation to complete with the dialog still showing. I've tried creating a new container within the application container which implements MCoeControlObserver and provides its own HandleControlEventL(CCoeControl* aControl, TCoeEvent aEventType). I have set the observer of the dialog to be the embedded container. However, I have not been able to get the dialog to fire events to the control observer when a selection is made.
Here's my construct code for the container:

void CMyContainer::ConstructL()
   {
   TBuf<20> myHost;
   myHost = _L("212.58.224.125");
       TInt myPort = 1;

   dialog = CAknMultiLineDataQueryDialog::NewL(myHost, myPort);   

   dialog->SetContainerWindowL(*this);

   TRect containerRect=Rect();
   SetRect(containerRect);
   dialog->ExecuteLD(R_SOCKETS_DIALOG_CONNECT);
   }

anyone got any ideas? I get the feeling I'm approaching the problem in the wrong way.

thanks in advance for any help
chris