For what it's worth, the instructions that came with my kit are numbered H001SSC200, which is for a 2011-2013 Forester. I contacted the site I purchased the kit from, and they assured me that the instructions were generic.
I tested the system with the hood down as shown, and the remote starter works fine.
What am I missing?
edit: I have searched this site and Google, and can't find any pictures of an engine bay on a 2008-9 Legacy with this switch.