I've hit Herman with the Coconut, the Bottle AND the bloody accordion and the old fart still wont give me the Gubernatorial symbol. I'm afraid I've had to resort to reading the walkthrough to check if I've done everything; it seems that I have. Have I still missed something? Does the milk bottle have to contain anything? I even hit him with all 3 in a row (talking to him in between) and all he says is "Where Ha!". If I could I'd throttle the sod!
Start with the coconut because the nut is the reason why he lost his memory in the first place. Throw it and talk to him until he remembers his name. Then stop throwing the nut otherwise he goes back to be a vegetable. Save the position and use the bottle and accordion. Talk and check how much he remembers. This way HT will finally regain memory and he will tell you a long story.