Hiya sounds like youve tried most things eh ?? have you ever read Jan Fennell the dog listener there is a low budget programe on one of the cable channels too . She is so good at these types of issues often putting a lot of this behaviour down to the dog beliving its his job to look after the house and the occupants of it , she uses a repetetive action to a behaviour such as barking when people come to the house . She would sit in the lounge not give eye contact to the dog the owner walks into the room with the dog on the lead if the dog barks she tells the owner not to speak and just walk out of the room and trying again a few mins later again if the dog barked the owner was told to leave the room without saying anything to the dog it took several attempts but the dog got the message that if he barked he was removed and only when he could be bought in the room without barking was he allowed to stay. when visitors come to the house and they speak to the dog first because they have no choice ask your visitors not to speak to the dog to ignore him no matter how much he tries to be the focus of attention . Its all about showing who,s boss and often dogs belive they are because they dont see you as effective leaders ,so doing things like gesture eating ,when you feed him let him see you eat something first as boss you would eat first and then when your ready put down his food . Barking in the garden is difficult but if you try to break his belief that its his job to bark with some of the other things he may be more willing to listen when he is outside too , Good luck and do look at Jan Fennels books she has her own web site and her first book is probably of best use to you

Andrea