I'm trying to limit an "Achievement" so that it can't be built repeatedly like normal improvements (Soil Enhancement, et al). What I've done:
//------------------------------------------------------------------------
IMPROVEMENT RecyclingPlants
//------------------------------------------------------------------------
Name "Atomic Recycling Plants"
Model "ManufacturingCapital"
Manufacturing_Bonus 40 //Manufacturing Bonus
Morale_Bonus 15 //Morale Bonus
Economic_Bonus 40 //Economic Bonus
Prestige_Bonus 0 //Prestige bonus
Planetary_Defense_Bonus 0 //Planetary Defense Bonus
Starship_Quality_Bonus 0 //Starship quality bonus
Research_Improvement_Bonus 0 //Research Improvement bonus
Type "Achievement"
Tech_Requirement_ID 700 //Atomic Recyling
AI 10
ID 11
AbilityType 0
AbilityAmount 0
Description "Atomic Recycling Plants boost our economy and production while simultaneously letting us clean up our environment."
Cost 350 //Cost
Maintenance 0
ENDIMPROVEMENT
The Model is set to "ManufacturingCapital" (in case there was some hard-coded relationship between the Model and the build limit, like Model "TradeGoods"), and Type is set to "Achievement". It shows up fine and works fine, but isn't limited to one per civilization - it can be built on multiple planets like a normal improvement. I can't find anything in your tutorial that addresses this, but I think that's because your tutorial was written for the normal improvements. Right now I have the option of reducing the bonuses and making it a normal improvement or turning it into a trade good.
Maybe a bug, but try some of these to see if they work:
1) Try putting it in achievements.imp (if it's not)
2) Put it at the bottom of achievements.imp, but put it in TWICE (remember how they used to have placeholders at the end of the file)
3) Change ID number to something else (mabe 21)
4) As a last ditch replace one o fthe achievements just as a test. Maybe something in the game is hardcoding only using the first 10 achievements...
5) Good luck! Report your findings so we can all see what works... or rather what doesn't