If you have a test light or multimeter switch the ignition key to the last position before starting the engine, drop the fuse box cover and test the fuses. Find one that is live and then switch it back one notch on the key and see if it goes out, if it does find out what the fuse is for. If it runs to the engine bay great, if not note which fuse it was and test another until you find one, if there isn't you have listed the one that run live on the last notch of the ignition.
You can tap into this live at the fuse box and push the wire through the engine loom gromet into the engine bay and up to the lights. Fingers crossed you should find a ignition live in the engine bay to tap into but can't think of one right now.
