Vince, SQLArg0 will have the first startup option, no matter which one it is. You need check each possible one until the desired startup option is found or the key does not exist. It's annoying. There can several options (e.g., trace flags). SQLArg0,..., SQLArg10,....
Andy, if you have more than a few dozen SQL Servers, it helps to use these tools to standardize the installation and setup via scripts. The GUI leaves too much room for mistakes by large teams. It's also easier to just run the script. There is a SMO Setting class of some sort, but I think it has a warning that it's going away in a future version. I'm stickin' with the xp version until I'm forced to do otherwise. It's nice when something does not have to be fixed with each version - getting too old for much more of that.
Helpdesk: "Perhaps I'm not the only one that does not know what you are doing." ;-)