yes it worked!
Had to put the top part in a vice. And then used pliers to turn the ring. Took some effort. The threads gave a lot of resitance, but then suddenly it came loose. Didn't damage the light or threads. Can't be too careful with things like these when it's your first try. Anyway, the ceramic slug has replaced the original slug and my light is working again, with a 1160 bulb.
Maybe I'll replace it with a 5761 bulb, but I already have two 2D mags mods with a 5761 bulb.
If anyone experiences trouble with replacing this slug --> ask me, now I know how it works [can explain it with pics].
thanks FM.
iapyx