I'm using gibbed editor to set DLC Arrival as succesfully completed. But it doesn't work. I set 7451 as true and still Anderson blames Shepard in blowing up the mass relay in Batarian's system. Why? Is there any more plot ids need to be set? And what plot ids add Conrad Verner into game? Thank you.
That seems to be working as intended.
The Arrival DLC ends up with Shepard blowing up the Alpha Relay and sacrificing a Batarian colony in the process. At the beginning of Mass Effect 3, Anderson uses that as explanation for Shepard's incarceration.
If Arrival isn't completed, then the Alliance's 103rd Marine Division is said to have carried out that mission and destroyed the Alpha Relay, but didn't make it out alive. In that instance, Anderson will blame Shepard for working with Cerberus to explain the incarceration.