Custom Tech Trees can't be done in campaign editor

[DwarfBoy]

Okay, so, I was going to try to make a campaign about trolls who take back their lands from a human kingdom, while they had a rebellion going on, and elves were planning on wiping them all out. However, I ran into some problems. Apparently, I can't use custom units to create requirements, like the tower I have in the screenshots. Is there... something wrong with it?

 

[teozamait]

You can do it in the Campaign editor as long as you have a map from that campaign opened in the background.