precondition: limit workitem types to iteration types

Hey Everyone,

We are trying to create a precondition to limit the type of workitems that can be planned against iterations with a certain iteration type - for instance to keep tasks away from a product backlog or making plan only with a custom workitem type.

now this precondition should be activated on the save workitem and should be created as an advisor but I dont know how to extract the iteration type and the workitem type from the IWorkItem I guess its stored in the getTarget() but I dont know how to handle this.

My sample code :

public class ExampleOperationAdvisor implements IOperationAdvisor {

public void run(AdvisableOperation operation,
IProcessConfigurationElement advisorConfiguration,
IAdvisorInfoCollector collector, IProgressMonitor monitor)
throws TeamRepositoryException {

Object data = operation.getOperationData();
if (data instanceof ISaveParameter) {
ISaveParameter saveParameter = (ISaveParameter) data;
IAuditableCommon auditableCommon= saveParameter.getSaveOperationParameter().getAuditableCommon();
IWorkItemCommon workItemCommon= auditableCommon.getPeer(IWorkItemCommon.class);
IAuditable auditable = saveParameter.getNewState();


if (auditable instanceof IWorkItem)
{

IWorkItem workItem = (IWorkItem) auditable;