One way would be to use a mains relay and connect the switched output to the SM10E.
There are outdoor X10 PIRs but most come with a spotlight already attached. But can't find anywhere that sells them at the moment.
Have a look at the MS13. It isn't really 100% waterproof and needs to be in a sheltered location if you are going to use them outside. I've installed them in porches or similar locations.