I tried to add new sides in Red Alert 2 by extending the list of Countries in the Rules.ini file. This Idea first came to my mind when I renamed the rulesmd.ini into a rules.ini. after that I run Red Alert 2. I have noticed that yuri's side is selectable in the skirmish section. So I decided to add a new side. and It worked.

heres what i've done
(Rules.ini)
[Countries]
0=Americans
1=Alliance
2=French
3=Germans
4=British
5=Africans
6=Arabs
7=Confederation
8=Russians
9=YuriCountry
10=NewCountry
11=GDI
12=Nod
13=Neutral
14=Special

[Sides]
;GDI=GDI
;Nod=Nod

GDI=British,French,Germans,Americans,Alliance
Nod=Russians,Africans,Confederation,Arabs,NewCountry
ThirdSide=YuriCountry
Civilian=Neutral
Mutant=Special

-&-

****** Country Statistics *******

[NewCountry]
UIName=Name:NewCountry
Name=NewCountry
Suffix=Soviet
Prefix=B
Color=DarkRed
Multiplay=yes
Side=Thirdside
SmartAI=yes

The Problem is whenever I rename it again into rulesmd.ini It Doesn't Include the "NewCountry" anymore. There seems to be a "lock" placed on Yuri which limits the country list on only 9 selectable factions or sides. Is there a way to decode this? I mean extend the list of countries on Yuri?