Unlock Export Office | Forums

[xplock]

Hi there!
I'm playing S7, my mission is to establish a export office for trading stone.
Now the problem: I simply can't unlock the export office... I'm stuck in here, don't know what to do to unlock it :\
By the way, my prestige level is 4.
I really apreciate anyone's help to overtake this problem.

Thanks
xplock

P.S.: Sorry for my bad English

[xplock]

I actually solved the problem!... I need to unlock the "Stronghold, Export office and Church" ****on, on the prestige tree!
Thank you very much, anyway