I don't believe you can pass parameters to a stored procedure. I'm checking on this, but in the meantime, since you're passing a single integer parameter, a workaround would be to use an SQL statement to call the stored procedure.
When you create a data connection using SQL instead of a stored procedure, you can alter the SQL statement from script via:
$sourceSet.MyConnection.#command.query.select.nodes.item(0).value = "SELECT * FROM FOO";
where MyConnection is the name of your data connection.
I don't have an SQL Server instance handy to try this on but I believe using something like:
EXEC procname 123
So you'd use that in place of the "SELECT..." statement.
Let me know if this works for you.
--
SteveX
Adobe Systems