private ArrayKey createKeyForHUProducer(final I_M_HU_LUTU_Configuration lutuConfiguration) {
    Check.assumeNotNull(lutuConfiguration, "lutuConfiguration not null");

    final List<Object> keyItems = new ArrayList<Object>();

    //
    // LU: PI
    final int luPIItemId = lutuConfiguration.getM_LU_HU_PI_Item_ID();
    final boolean hasLU;
    if (luPIItemId > 0) {
      final int luPIId = lutuConfiguration.getM_LU_HU_PI_ID();
      Check.assume(luPIId > 0, "LU PI ID shall be set for {}", lutuConfiguration);

      keyItems.add(luPIItemId); // LU M_HU_PI_Item_ID
      keyItems.add(luPIId); // LU M_HU_PI_ID
      hasLU = true;
    } else {
      keyItems.add(-1); // LU M_HU_PI_Item_ID
      keyItems.add(-1); // LU M_HU_PI_ID
      hasLU = false;
    }

    //
    // LU: Qty
    // NOTE: we skip QtyLU because it's not relevant when we check if the configuration is still
    // compliant with an HU

    //
    // TU: PI
    final int tuPIId = lutuConfiguration.getM_TU_HU_PI_ID();
    if (tuPIId > 0) {
      keyItems.add(tuPIId); // TU M_HU_PI_ID
    } else {
      keyItems.add(-1); // TU M_HU_PI_ID
    }

    //
    // TU: Qty
    if (lutuConfiguration.isInfiniteQtyTU()) {
      keyItems.add(true); // IsInfiniteQtyTU
      keyItems.add(0); // Qty TU
    }
    // case: there is no LU. In this case we can ignore the QtyTU because it's not relevant when we
    // check if configuration is still compiant with an HU
    else if (!hasLU) {
      keyItems.add(false); // IsInfiniteQtyTU
      keyItems.add("QtyTU_NA"); // Qty TU: N/A
    } else {
      keyItems.add(false); // IsInfiniteQtyTU
      keyItems.add(lutuConfiguration.getQtyTU().intValue()); // Qty TU
    }

    //
    // CU
    final int productId = lutuConfiguration.getM_Product_ID();
    final int uomId = lutuConfiguration.getC_UOM_ID();
    keyItems.add(productId > 0 ? productId : -1);
    keyItems.add(uomId > 0 ? uomId : -1);
    if (lutuConfiguration.isInfiniteQtyCU()) {
      keyItems.add(true); // IsInfiniteQtyCU
      keyItems.add(BigDecimal.ZERO); // Qty CU
    } else {
      final BigDecimal qtyCU = NumberUtils.stripTrailingDecimalZeros(lutuConfiguration.getQtyCU());
      keyItems.add(false); // IsInfiniteQtyCU
      keyItems.add(qtyCU); // Qty CU
    }

    //
    // Misc
    final int locatorId = lutuConfiguration.getM_Locator_ID();
    final int bpartnerId = lutuConfiguration.getC_BPartner_ID();
    final int bpartnerLocationId = lutuConfiguration.getC_BPartner_Location_ID();
    final String huStatus = lutuConfiguration.getHUStatus();
    keyItems.add(locatorId > 0 ? locatorId : -1);
    keyItems.add(bpartnerId > 0 ? bpartnerId : -1);
    keyItems.add(bpartnerLocationId > 0 ? bpartnerLocationId : -1);
    keyItems.add(huStatus);
    keyItems.add(lutuConfiguration.isActive());

    return Util.mkKey(keyItems.toArray());
  }