I have a really simple stored procedure that looks like this:

CREATE PROCEDURE _Visitor_GetVisitorIDByVisitorGUID
(
 @VisitorGUID AS UNIQUEIDENTIFIER
)

AS

DECLARE @VisitorID AS bigint

SELECT @VisitorID = VisitorID FROM dbo.Visitor WHERE VisitorGUID = @VisitorGUID

--Here's what I've tried 
RETURN @VisitorID 'Returns an IDataReader
SELECT @VisitorID 'Returns an IDataReader
--I've also set it up with a single output
--parameter, but that means I need to pass
--the long in by ref and that's hideous to me

I'm trying to get nettiers to generate a method with this signature:

public long VisitorService.GetVisitorIDByVisitorGUID(GUID visitorGUID);

Basically I want Nettiers to call ExecuteScalar instead of ExecuteReader. What am I doing wrong?