hella late response, but if you haven't found it already, you need to look for a space encounter with a blue icon (swirl thing) instead of a purple one

I sacrificed my FU universe to the void after realizing it made the Elithian Alliance mod so much harder to play with. I'm not sure but I wouldn't be surprised if the special encounters (the blue swirlies) could only generate in the original star systems (Frozen stars, etc.). I'm not sure if the star has to be of a certain level/difficulty for the encounter to appear but I would start by checking the Firey stars first. If all else fails, you can always use a /warp command and look at the elithian alliance github for the id of Vhos Avha'las. Good luck!