SQL Server ::trying To Use A Stored Procedure In My Codebehind Insted Of A Sqldatasource To Insert Some Data?

I'm trying to use a stored procedure in my codebehind insted of a sqldatasource to insert some data, and return the identity fields. But I keep getting tripped up on the output paramaters. What am I missing?

My code behind:

[Code]....

And, here's my stored procedure

Create PROCEDURE [dbo].[123]
(
@MatterToCloneID varchar(15),
@ClonedMatterID int OUTPUT,
@ClientIDOUT int OUTPUT,
@ExistingClientIDOUT int OUTPUT
)
AS
BEGIN
DECLARE
@ExistingClientID int,
@PendingClientID int,
@BillingAddress varchar(200),
@BillingCity varchar(200),
@BillingState varchar(100),
@BillingZipCode varchar(20),
@BillingCountry varchar(200)
SELECT @ExistingClientID = ExistingClientID, @PendingClientID = PendingClientID,
@BillingAddress = BillingAddress, @BillingCity = BillingCity, @BillingState = BillingState, @BillingZipCode = BillingZipCode, @BillingCountry = BillingCountry
FROM tNewMatters
WHERE MatterID = @MatterToCloneID
Set @ClientID = @EClientID
Set @PendingClientID = @PendingClientID
Set @BillingAddress = @BillingAddress
Set @BillingCity = @BillingCity
Set @BillingState = @BillingState
Set @BillingZipCode = @BillingZipCode
Set @BillingCountry = @BillingCountry
INSERT into tNewMatters
(MatterName, ClientID, PendingClientID, BillingAddress, BillingCity, BillingState, BillingZipCode, BillingCountry)
Values
('Enter Client Name', @ExistingClientID, @PendingClientID, @BillingAddress, @BillingCity, @BillingState, @BillingZipCode, @BillingCountry)
Select @ClonedMatterID = scope_identity()
Select @ClientIDOUT = @ClientID
Select @ExistingClientIDOUT = @ExistingClientID
END