Create a shortcut to your BI exe and add the mod switch to it ("-mod:EB"). Then copy paste the "imperial_campaign" folder from "\EB\Data\world\maps\campaign" and rename the copy to "barbarian_invasion".
They're may be more but that's all I remember for right now, I suggest you try Ferromancers mod again though, just checked the link is working fine now.
Cheers
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