New resources?

I've seen the same question asked on twcenter, no answer there, maybe somebody here knows the answer? I'm trying to add new resources, but they don't work.
The files I've tried to modify are:
main resource file
text/strat.txt
text/tooltips.txt
Nothing works. I get the error saying the game doesn't recognize the new resources.
Don't tell me it's ANOTHER hard-coded thing!

Heres an idea for new resources:

There are two unused resources, pigs and dogs. Rename them, and that gives you two more.

Camels and Elephants could be replaced by hidden resources, that makes another two.

I don't like wild animals, so if you replace that, it makes five extra.

Elephants get to stay, we need Ivory... and I need more than four new resources, if possible... didn't anyone manage to do it?

I tried, and failed, don't know about anyone else