Problem Returning Data

I have a stored procedure (in SQL Server 2005 Express) that returns a string.  The problem is when I call it from my web page I get only the first character of the string.  This is my SP:

ALTER PROCEDURE dbo.usp_CalcDeliveryCharge

@mintDistance int,

@mintCustomer_ID int = 0,

@mintRate int = 0 OUTPUT,

@mstrZone nchar(10) = null OUTPUT

AS



/* SET NOCOUNT ON */



SELECT @mintRate=RATE,

@mstrZone=ZONE

FROM tblRates

WHERE Customer_ID=@mintCustomer_ID

AND Mile_Range_Min <= @mintDistance

AND Mile_Range_Max >= @mintDistance

 

And this is my code:

sql_Command.CommandText = "usp_CalcDeliveryCharge"

sql_Command.CommandType = CommandType.StoredProcedure

sql_Command.Parameters.Clear()

sql_Command.Parameters.AddWithValue("@mintDistance", intApproxMiles)

sql_Command.Parameters.AddWithValue("@mintCustomer_ID", Profile.CompanyID)

sql_Conn.Open()

sql_Reader = sql_Command.ExecuteReader()

While (sql_Reader.Read())

Me.lblZone.Text = sql_Reader.Item(0).ToString

End While

sql_Conn.Close()

sql_Reader.Close()

sql_Command.Dispose()