Invoking Castor via Ant Task, w/in WebSphere

We have a Web project set up for a WebService. We are using Castor to generate the java objects from the xsd. A coworker (who has since left, leaving me to support this) wrote an Ant Task to call Castor whenever the project is Rebuilt. All I think I know is he did this by adding it as an External Tool Builder in the project properties.

It was working fine for awhile, now it's not. I have very little experience with Ant. The weird, new problem is that it appears as if it's not writing any of the classes when the project is Rebuilt. But there are no compilation problems reported in the Tasks view.

Included in this project is a JUnit that we use to test the WebService. The problem now is that JUnit is saying that the JUnit class cannot be found.

Has anyone done something similar? Any tips or ideas?

Thanks