No siren & lights on Add-on vehicle

Hello everyone!

So I recently got tired of constantly having to replace the standard police vehicles to other and better ones that fits my desire, so I went to the internet and I installed this pack which I know is a bit outdated and old, but I decided to give it a go. I then installed bxbugs' slicktop CVPI and followed the readme that comes with the pack, double checked everything and then when I go into the game and spawn the vehicle in, the vehicle is spawning with all the textures etc. - nothing wrong there, but when I press "E" or "1,2,3,4,5"(SirenMasterykeys) there is no lights or siren. I tried adding the car to the SirenMastery.xml file, but nothing changed. I also do use ELS, but I don't know if that has anything to do with it at all..

I did also check if it had the right flags and it did..

If someone out there knows what could be wrong here, please let me know in the comments. Also tell me if you need any screenshots or stuff like that. :)

Thank you.

- TheNuttyDane.