Linq to Sql: Stored Proc with multiple resultsets not working with IMultipleResultset

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SQL-Server

LINQ

Hello.
I have a stored procedure that returns 3 different resultsets. I'm dragging this stored proc into my dbml file and want to return all 3 different resultsets using IMultipleResults, however when I try to request my 2nd and 3rd resultsets, they for some reason, still only return the 1st resultset again. I need to be able to retrieve these 2nd & 3rd results.
Here's my code in my datacontext file:

[Function(Name="dbo.MyStoredProcName")]
        [ResultType(typeof(InventoryTransactions))]
        [ResultType(typeof(Shipments))]
        [ResultType(typeof(Receipts))]
        public IMultipleResults GetMultipleRs()
        {
            IExecuteResult result = this.ExecuteMethodCall(this, (MethodInfo) MethodInfo.GetCurrentMethod());
            return (IMultipleResults) result.ReturnValue;
        }

Then, I call it from one of 3 different methods. All 3 are listed below. The only difference between the 3 is each one attempts to return a different resultset (InventoryTransactions, Shipments, & Receipts):

public List<inventorytransactions> GetIlsInventoryTransactions(DateTime startDate, DateTime endDate)
        {
            List<inventorytransactions> transactions;

            using (IlsDataContext dc = _conn.GetIlsTransactionContext())
            {
                IMultipleResults ret = dc.GetMultipleRs();
                transactions = (from t in ret.GetResult<InventoryTransactions>()
                                where t.DateTimeStamp >= startDate && t.DateTimeStamp < endDate
                                select t).ToList();
            }
            return transactions;
        }

public List<Shipments> GetIlsShipments(DateTime startDate, DateTime endDate)
        {
            List<Shipments> transactions;

            using (IlsDataContext dc = _conn.GetIlsTransactionContext())
            {
                IMultipleResults ret = dc.GetMultipleRs();
                transactions = (from t in ret.GetResult<Shipments>()
                                where t.DateTimeStamp >= startDate && t.DateTimeStamp < endDate
                                select t).ToList();
            }
            return transactions;
        }



public List<Receipts> GetIlsReceipts(DateTime startDate, DateTime endDate)
        {
            List<Receipts> transactions;

            using (IlsDataContext dc = _conn.GetIlsTransactionContext())
            {
                IMultipleResults ret = dc.GetMultipleRs();
                transactions = (from t in ret.GetResult<Receipts>()
                                where t.DateTimeStamp >= startDate && t.DateTimeStamp < endDate
                                select t).ToList();
            }
            return transactions;
        }</inventorytransactions></inventorytransactions>

--------------------------------------------------------------------------------
When I call any of these 3 methods, all 3 only return the data from the 1st resultset (InventoryTransactions). Any idea why I can't get the 2nd and 3rd ones?
Thanks.