The workaround is simple and I'm already using it: you place an object-type MCD that emits light in the same spot of the wannabe-lighting-wall.
I do this for the wall lamps in my mod but it comes with drawbacks.
First, if the wall is destroyed the lamp stays there "floating"; not exactly a common occurrence but it looks ugly when it happens.
Second, the object-type MCD need a Foootstep_Sound:51 option.. and it means that if you are walking on a tile containing a wall-hanging object, you can -potentially- suddenly hear a different sound, which again is annoying.
Honestly, now that I recall the advanced lighting of OCXE, I guess making light-emitting walls is probably quite hard and not worth it. Should have considered that before making the request.