My Output Parameter Is Being Treated As An Input Parameter...why

I have a stored procedure which takes an input parm and is supposed to return an output parameter named NewRetVal.  I have tested the proc from Query Analyzer and it works fine, however when I run the ASP code and do a quickwatch I see that the parm is being switched to an input parm instead of the output parm I have it defined as...any ideas why this is happening?  The update portion works fine, it is the Delete proc that I am having the problems...
 ASP Code...
<asp:SqlDataSource ID="SqlDS_Form" runat="server" ConnectionString="<%$ ConnectionStrings:PTNConnectionString %>" SelectCommand="PTN_sp_getFormDD" SelectCommandType="StoredProcedure" OldValuesParameterFormatString="original_{0}" UpdateCommand="PTN_sp_Form_Update" UpdateCommandType="StoredProcedure" OnUpdated="SqlDS_Form_Updated" OnUpdating="SqlDS_Form_Updating" DeleteCommand="PTN_sp_Form_Del" DeleteCommandType="StoredProcedure" OnDeleting="SqlDS_Form_Updating" OnDeleted="SqlDS_Form_Deleted">
<UpdateParameters><asp:ControlParameter ControlID="GridView1" Name="DescID" PropertyName="SelectedValue" Type="Int32" /><asp:ControlParameter ControlID="GridView1" Name="FormNum" PropertyName="SelectedValue" Type="String" /><asp:Parameter Name="original_FormNum" Type="String" /><asp:Parameter Direction="InputOutput" size="25" Name="RetVal" Type="String" /></UpdateParameters>
<DeleteParameters>
<asp:Parameter Name="original_FormNum" Type="String" />
<asp:Parameter Direction="InputOutput" Size="1" Name="NewRetVal" Type="Int16" />
</DeleteParameters>
</asp:SqlDataSource>
Code Behind:

protected void SqlDS_Form_Deleted(object sender, SqlDataSourceStatusEventArgs e)
{
  if (e.Exception == null)
    {   string strRetVal = (String)e.Command.Parameters["@NewRetVal"].Value.ToString();
    ............................
Stored Procedure:CREATE PROCEDURE [dbo].[PTN_sp_Form_Del] (
@original_FormNum nvarchar(20),
@NewRetVal INT OUTPUT )
AS
SET NOCOUNT ON
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

DECLARE @stoptrans varchar(5), @AvailFound int, @AssignedFound int

Set @stoptrans = 'NO'

/* ---------------------- Search PART #1 ----------------------------------------------------- */
SET @AvailFound = ( SELECT COUNT(*) FROM dbo.AvailableNumber WHERE dbo.AvailableNumber.FormNum = @original_FormNum )
SET @AssignedFound = ( SELECT COUNT(*) FROM dbo.AssignedNumber WHERE dbo.AssignedNumber.FormNum=@original_FormNum )

IF @AvailFound > 0 OR @AssignedFound > 0 /* It is ok if no rows found on available table, continue on to Assigned table, otherwise stop the deletion.*/
-----This means the delete can't happen...........
BEGIN

IF @AssignedFound > 0 AND @AvailFound = 0
BEGIN
SET @NewRetVal = 1
END

IF @AssignedFound > 0 AND @AvailFound > 0
BEGIN
SET @NewRetVal = 2
END

IF @AssignedFound = 0 AND @AvailFound > 0
BEGIN
SET @NewRetVal = 3
END
END

ELSE
BEGIN
DELETE FROM dbo.Form
WHERE dbo.Form.FormNum=@original_FormNum

SET @NewRetVal = 0
---Successful deletion
END
GO

 --------------------------------------------------------
  When I go into the debug mode and do a quickwatch, the NewRetVal is showing as string input.