EP1 Content on CSS?

Hey, i’d like to know if it’s possible to import EP1 Content into a CSS Map? Maybe using pakrat or something?

I’m making a map, and i used tried to use the prop_coreball and some props from the core map and on hammer it shows up as obsolete and the props as errors… and ingame nothing appears.

On GMOD it works btw.

prop_coreball is an actual entity coded into Ep1. It doesn’t exist in CS:S. Copying over the model will only stop the error models in Hammer, but it still won’t show in-game.