use and lifecycle of IAsyncResult object in Asynchonous Consuming of XML Web Service

[johnmann56]

Hello, I'm a newbie to Web Services and have a question about consuming XML Web Services asynchronously. I gather so far that the IAsyncResult object returned from BeginXXX method of a proxy class is important, as it gets used later by the EndXXX method. I'm working an example from Freeman and Jones "XML Web Services Step by Step", Chapter 15, and wonder where the important IAsyncResult object GOES or is stored, to be used later, in the following code line

o_validator.BeginValidateCard(x_object, x_callback, Result1)

where o_validator is an instance of a proxy class for an XML Web Service that validates credit card numbers. Any help would be appreciated