My reply had two parts:

1. How to do it in SQL Server

2. How to do it in ADO.Net

Example of Calling a SQL Server SP with an return parameter (@RC):

DECLARE @rc int

DECLARE @WinderReel int

DECLARE @JumboSet tinyint

DECLARE @CullTime smalldatetime

DECLARE @Diameter decimal(9,3)

EXECUTE @rc = [LabNet].[dbo].[jpCullSetFetch]

...