Oh, it's there. I think it is in the episode when [spoiler] Barn rings Collinwood and tells Julia she needs to come to Dr Lang's house and bring her medallion... to hypnotise Jeff and make him forget that Lang was going to cut off his head to serve as Adam's face[/spoiler]. I can give you the episode number later this evening, if somebody else doesn't get to it beforehand.
If I'm remembering correctly, however, in the above Julia and Cassandra are on their way to have lunch with Stokes. It's in a later episode that Julia refers to the conversation about the occult.
Ah, an excuse to re-watch some Cassandra episodes! Happy!
cheers, Steve