Problem assigning a operation to a StartEvent

[Compadre]

Hi,

I'm following the BPEL A Step by Step Guide (http://www.sparxsystems.com/downloads/quick/bpel_model_driven_generation.pdf), trying to create the HelloWorld BPEL example and when I try to assign an WebService operation to the StartEvent, as show in Page 10 of the guide (Modifying the BPEL Process to suit Hello World example) the dialog Select an Asynchronous Operation is empty. I follow every step of the example and didn't find what I was doing wrong.

Hope someone can help me.

Thanks

Compadre