Additional columns to the Location column lookup of the Sales Orders form

Hi community! 

I am trying to add extra columns to the Location lookup on the Details tab of the Sales Order form. 
I tried the following, but it is showing only the new columns and removing the original ones 

    public class SOOrderEntry_Extension : PXGraphExtension<PX.Objects.SO.SOOrderEntry>
    {
        #region CacheAttached
        [PXMergeAttributes(Method = MergeMethod.Merge)]
        [SOLocationAvail(typeof(SOLine.inventoryID), typeof(SOLine.subItemID), typeof(SOLine.costCenterID), typeof(SOLine.siteID), typeof(SOLine.tranType), typeof(SOLine.invtMult))]
        [PXCustomizeSelectorColumns(
                typeof(PX.Objects.IN.INLocation.locationCD),
                typeof(PX.Objects.IN.INLocationStatus.qtyAvail),
                typeof(PX.Objects.IN.INLocationStatus.qtyOnHand),
                typeof(PX.Objects.IN.INLocationStatus.active),
                typeof(PX.Objects.IN.INLocation.receiptsValid),
                typeof(PX.Objects.IN.INLocation.salesValid),
                typeof(PX.Objects.IN.INLocation.transfersValid),
                typeof(PX.Objects.IN.INLocation.projectID),
                typeof(PX.Objects.IN.INLocation.taskID),
                typeof(PX.Objects.IN.INLocation.primaryItemID),
                typeof(PX.Objects.IN.INLocation.primaryItemClassID))]
        public virtual void SOLine_LocationID_CacheAttached(PXCache sender) { }
        #endregion
    }

Could someone help me keep the original columns? 
Thanks!