IIRC you need both "engine exhaust" like texture to make beam visible and lightsource, however I don't recall it'll light up the ground (at least in Orbiter 2010).
In this example the only thing lit up are base objects and "vessels" like launchpads.
Not sure how it could be done. Spawning and despawning your EVA vessel would require something like definition in EVA vessel's cfg but that might pose some problems for vessels that need special parameters during spawning.
oMMU_spawnable_vessel = true;