Help Requested: Obtain exclusive lock with a Stored Proc

Who do you obtain an exclusive lock on a row from within a Stored Procedure? The SET LOCK MODE TO CURSOR STABILITY allows for a shared lock, now I am in a situation where I know a specific row will be updated and thus wish stop other users from accessing the row under all circumstances until such update has been committed. The FOR UPDATE clause on a Select statement provides a syntax error on compiling the stored procedure. Please reply directly or through the group. Thanks you Dennis Harding