I see this thread is active so I will dear ask my question here.
Is there any way to activate an Iphone 3gs 3.1.3, a newer baseband without the original sim card (AT&T), for I have reseted it and now it is quite useless, as I am form Moldova
Nope, u need a valid AT&T simcard.
Wait some more time. There will be a new jb that activates and probably unlock also.