How to get attachment history (not workitem history) by plain java api?

 I've managed to get the workitem history by the following code. But it doesn't work to get attachment add/removal history. RTC web ui & eclipse client have managed to do so. They keep a history of adding/removal attachments, and adding links. How to do this in plain java?

public List<abstractoutputdto> fetchWorkItemCompleteStates(ITeamRepository repo, int wiid, final String outputType) throws TeamRepositoryException, RTCAdapterException {
    final ResettingTimer t = new ResettingTimer(this, true);
    final IWorkItem currentWi = this.getWIByID(repo, wiid);
    DevLog.super_trace("current wi stateId: " + currentWi.getStateId().getUuidValue());
    final IItemManager itemManager = repo.itemManager();
    // ATTACHMENT
    IWorkItemWorkingCopyManager wcm = this.getWCM(repo);
    wcm.connect(currentWi, IWorkItem.FULL_PROFILE, null);
    WorkItemWorkingCopy wc = wcm.getWorkingCopy(currentWi);
    List<ireference> rL = wc.getReferences().getReferences(WorkItemEndPoints.ATTACHMENT);
    DevLog.debug("---------->"+rL.size());
    List<iattachmenthandle> aL = wc.getReferences().getDeletedAttachments();
    DevLog.debug("deleted attachment size:L "+aL.size());
    for (IAttachmentHandle atmtH : aL) {
        final IAttachment atmt = (IAttachment) repo.itemManager().fetchCompleteItem(atmtH, IItemManager.DEFAULT, null);
        final AtmtInfoOutputBO aiob = new AtmtInfoOutputBO();
        aiob.setAtmtName(atmt.getName());
        aiob.setDescription(atmt.getDescription());
        aiob.setCreationDate(atmt.getCreationDate() == null ? null : atmt.getCreationDate().toString());
        aiob.setId(atmt.getId());
        DevLog.debug("----eleted attachment: "+Invoker.reportObj(aiob));
    }
    // state handle list
    final List<iauditablehandle> shL = itemManager.fetchAllStateHandles((IAuditableHandle) currentWi.getItemHandle(), null);
    List<iworkitem> wiL = new ArrayList<iworkitem>();
    t.lapAndReset();
    wiL = itemManager.fetchCompleteStates(shL, null);
    t.lapAndReset();
    Class<? extends AbstractOutputDTO> oc = this.getClassByOutputType(outputType);
    DevLog.super_trace("output dto class decided to be: " + oc.getCanonicalName());
    final List<abstractoutputdto> odL = new ArrayList<abstractoutputdto>();
    for (IWorkItem stateWi : wiL) {
        DevLog.debug("Converting stateWi id: " + stateWi.getId());
        try {
            // final AbstractOutputDTO od = EnrichOByWIS.ins.enrichOByWI(repo, stateWi, oc);
            UDStateOutputDTO od = new UDStateOutputDTO();
            od.setModifiedDate(stateWi.modified().toString());
            od.setStateId(stateWi.getStateId().getUuidValue());
            // CONTRIBUTOR
            final Contributor c = (Contributor) repo.itemManager().fetchCompleteItem(stateWi.getModifiedBy(), IItemManager.DEFAULT, null);
            od.setModifiedBy_name(c.getName());
            od.setModifiedBy_emailAddress(c.getEmailAddress());
            DevLog.super_trace("returned state: " + Invoker.reportObj(od));
            odL.add(od);
        } catch (TeamRepositoryException e) {
            e.printStackTrace();
        }
        /
        * catch (IllegalAccessException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); }
        /
    }
    t.lapAndReset();
    return odL;
}