How to create Build Definition via SDK API?

I got the cause, since the processAreaHandle is null in my code.
If set the para right, the definition created correctly.

Thanks!

I find the following code in SDK test jar, but run with expection, any one can help?
String templateId = "com.ibm.team.build.ant";

	  private static IBuildDefinition createBuildDefinition(ITeamRepository repo, IProcessAreaHandle processAreaHandle, String templateId, String definitionId) throws Exception {

		    IBuildDefinition definition = null;

		    IBuildDefinitionTemplate template = BuildConfigurationRegistry.getInstance().getBuildDefinitionTemplate(templateId);

		    if (template != null) {

		      definition = BuildItemFactory.createBuildDefinition();

		      definition.setProcessArea(processAreaHandle);

		      definition.setId(definitionId);

		      definition.initializeConfiguration(template);

		      definition = ClientFactory.getTeamBuildClient(repo).save(definition, new NullProgressMonitor());

		    }

		    return definition;

		  }

java.lang.IllegalArgumentException: Item Handle must not be null
at com.ibm.team.repository.service.internal.RepositoryItemService.fetchItem(RepositoryItemService.java:493)
at sun.reflect.GeneratedMethodAccessor276.invoke(null)

Thanks!