here is a routine in one of my programs. note that you must use the *.apt.* jar files from the sdk plugins
this is derived from Guido's code in https://jazz.net/forum/questions/82381/how-do-i-create-a-plan-with-the-java-api

    private static void createPlan(IAuditableClient destauditableClient,
            IProjectArea project, String planName,
            IIterationHandle planIteration, String planType,
            IItemHandle planTeam, String planinfo, IContributor creator)
    {
        // get classes for plan creation
        IAuditableCommon audit = (IAuditableCommon) destauditableClient.getTeamRepository().getClientLibrary(IAuditableCommon.class);
        IIterationPlanService planService = (IIterationPlanService) ((IClientLibraryContext) destauditableClient.getTeamRepository()).getServiceInterface(IIterationPlanService.class);

        // create necessary plan items
        IIterationPlanRecord plan = (IIterationPlanRecord) IIterationPlanRecord.ITEM_TYPE.createItem();

        IWikiPage wiki = (IWikiPage) IWikiPage.ITEM_TYPE.createItem();

        // setup plan values
        plan.setName(planName);
        plan.setIteration(planIteration);
        plan.setPlanType(planType);
        plan.setOwner((IProcessAreaHandle) planTeam);

        // setup wiki page
        wiki.setName("entry " + planName);
        wiki.setWikiID(IIterationPlanRecord.OVERVIEW_PAGE_ID);
        wiki.setCreator(creator);
        wiki.setOwner(plan);

        String encoding = "UTF8";
        String xmlText = "<p>test</p>";
        byte[] bytes;
        try
        {
            InputStream inputStream = null;
            if (planinfo != null)
            {
                bytes = planinfo.getBytes(encoding);

                inputStream = new ByteArrayInputStream(bytes);

                plan.setAuxiliaryData(audit.storeContent(IContent.CONTENT_TYPE_TEXT, encoding, inputStream, bytes.length, null));
            }

            bytes = xmlText.getBytes(encoding);

            inputStream = new ByteArrayInputStream(bytes);

            wiki.setContent(audit.storeContent(IContent.CONTENT_TYPE_TEXT, encoding, inputStream, bytes.length, null));
            // save plan
            DTO_IterationPlanSaveResult saveResult = planService.save(project, plan, wiki);
            if (saveResult.isSetIterationPlanRecord() == false)
            {
                System.out.println("Saving failed!");
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

    }