Ship Mod Question

[Spin]

Hello. I've been playing SEIV for a while and started modding recently. I've figured through most of it trial and error, but I'm stumped on one thing. In the VehicleSize.txt file, I'd like to add requirements to the ship types. When I add a REQUIREMENT at the bottom of the list and then run the game, my additons don't seem to register. I'm using the types of requirements listed at the top of the file, ie: Must Have, Cannot Have etc. Could anyone post an example of how to add different requirements?
Thanks in advance.

PS: I have to say that the mods here have been fantastic, both to play and as tools to get me started modding.