Hi,

I am trying to use linq to sql to call a stored procedure.

Here's the proc signature:

CREATE PROCEDURE [dbo].[apConvertDocument]
    @FromDocumentId int,
    @FromDocumentVersion timestamp,
    @CloseFromDocument bit,
    @NewDocumentType char(1),
    @NewDocumentId int output,
    @NewDocumentVersion timestamp output
AS
-- do stuff

Here's the code I'm using to call the sp:
        [Function( Name = "dbo.apCorrectInvoice", IsComposable = false )]
        public int apCorrectInvoice(
            [Parameter( Name = "DocumentId", DbType = "Int" )]
            int? documentId,
            [Parameter( Name = "DocumentVersion", DbType = "Timestamp" )]
            byte[] documentVersion,
            [Parameter( Name = "CreditMemoId", DbType = "Int" )]
            ref int? creditMemoId,
            [Parameter( Name = "CreditMemoVersion", DbType = "Timestamp" )]
            ref byte[] creditMemoVersion,
            [Parameter( Name = "NewInvoiceId", DbType = "Int" )]
            ref int? newInvoiceId,
            [Parameter( Name = "NewInvoiceVersion", DbType = "Timestamp" )]
            ref byte[] newInvoiceVersion
        ) {
            Binary tmp = new Binary( new byte[ 8 ] );
            Binary tmp2 = new Binary( new byte[ 8 ] );

            IExecuteResult result =
                ExecuteMethodCall(
                    this,
                    (MethodInfo)MethodInfo.GetCurrentMethod(),
                    documentId,
                    new Binary( documentVersion ),
                    creditMemoId,
                    tmp,
                    newInvoiceId,
                    tmp2
                );
            creditMemoId = (int?)result.GetParameterValue( 2 );
            creditMemoVersion =
( (Binary)result.GetParameterValue( 3 ) ).ToArray();
            newInvoiceId = (int?)result.GetParameterValue( 4 );
            newInvoiceVersion =
( (Binary)result.GetParameterValue( 5 ) ).ToArray();

            return (int)result.ReturnValue;
        }

No matter what I do, I get the following exception:
System.ArgumentException: Argument types do not match
  at System.Linq.Expressions.Expression.Constant(Object value, Type
type)
  at System.Data.Linq.DataContext.GetMethodCall(Object instance,
MethodInfo methodInfo, Object[] parameters)
  at System.Data.Linq.DataContext.ExecuteMethodCall(Object instance,
MethodInfo methodInfo, Object[] parameters)

Any ideas?