Steam - Steam apps - common - Age of Empires 3 - bin - data
After your done with creating your new homecity, rename or remove the "civs.xml" file
from your "data" folder. This will allow you to continue online.
You can also create an American Homecity online, but be sure to remove the "civs"
file in order not to have CRC Mismatch.
Be sure to run VANILLA AOE3 first, then try out the expansions.
It wont create the HC and new civ otherwise!
To acquire all the new cards you need to play on War Chiefs or Asian Dynasties.
Since the player starts with no explorer, I have added two maps, which start with Explorer and Major Cooper for the American Player. These work online.
Copy the Custom "American" Maps & the .xml files from RM3 into
My Documents - My Games - Age of Empires III - RM3
Then you will be able to play Custom "American" Maps with the starting explorer.
I have also added Bandeirantes card to be sent in Discovery Age.
Idea based on my own ideas and civs.xml.xmb taken from iamchanceless' "Special Civs on ESO" Mod.