Leo,
Just to make Quinn's post clearer...
Quinn is working with two sde geodatabases in the 2 way replica....he is adding new data from the File geodatabase(FGDB) in to the child sde gdb and then synchronizing the child with the parent sde gdb. Thats the only role of the FGDB here.
To confirm, for a 2-way replica.....both need to be sde geodatabase! A FGDB cannot be involved in a 2-way replica.
This is what I understand. Quinn please correct me if I'm wrong.
Regards,