If you want to change the properties on the attached light, you have to use set ... on. So set texture on flame in your instance. The example you've posted above is a bit confusing, as the entity itself already seems to be a light, so why is there an additional one attached?!
Obs, that's a stock TDM light, you can see it under Create entity>Lights>Model lights, Static>Gas. All I did was selecting Show inherited properties check-box in Entity tab, selecting "texture" and changing it from "lights/biground1" to something else. New value for that spawnarg appeared right under it, but it doesn't work in-game. So my guess was either the class system is borked, or something is inherited in a weird or wrong way. As I said before, using stuff like def_attach with invisible light radius and some intermeriary spawnargs is more like temporary workaround, not a real solution.
Let me show you how it should probably work, This is UE 2.x actor (entity) class window:
The structure is clear and simple, you go to world objects, choose a torch and place it in the map. Then you check the box to show inherited properties, and they appear on a current level (so in the entity placed in map). Then just change the values as you need, so they change from "grayed-out" to "active", and that's it. No doubled values, no intermediary variables.
There's nothing super-speedy about that workflow, it's just... normal. That's why I highly recommend studying other engines, at least from time to time, to blatantly steal their ideas Not from a coding perspective I guess, but in terms of stuff like structure, UX, and interface design. This is all tried-out and already proven stuff. It saves you time, so you don't have to reinvent the wheel.
That said, I tried to do something similar to above in DR, and came up with what I expected, the result was similar to Biker's. The light was at the model pivot point, although its properties are editable and the radius is visible, which is good. Using vertex mode or changing the light_center results in an unpredictable effect though, compare the position of the light center in the editor and how it looks in game:
Edited by Judith, 25 April 2018 - 10:29 AM.