Problem learning code using UsbManagedWrapper

[homevista]

Hi,
I am writing a simple program in C# with VS2005 to interface with the USBUIRT via the managed wrapper. I followed the TestApp implementation, but it failed to learn. The Learning and LearnCompleted events never get fired.
Do I have to hanlde Received event in order for Learning to work?
Any helps or suggestions would be appreciated.
Thanks,