Don't think you can change the General's speech. You have to kill him. You could try drugging him or putting some explosives on him. I got the murderer tag and still got to Vault 0 with the top Rep...Defender of the Wastes or whatever.
Has anyone tried to overdose him with ultrastims or truama packs, like in FO2? I shot him my first time through, and poisoned him the second, but I always got the same message from the General.
