It's all about forward planning
If you're going out shopping, before you go, sit him down, talk to him about where you're going, how long you will be and what he will be doing, acknowledge that you know he doesnt like it and nither do you but it has ot be done.
So something like "we have to go shopping for some new clothes, I know you find it boring, as do I, but it has to be done or we'd all be naked. So we will go in about 4 shops, we will be about an hour and then will come home. When we are there you are to stay with me, and not hit your brother or be rude to me. If you are good we will go to McDonald's/buy you a comic/all watch a DVD when we get home/go on your PS3 for an hour. If you run away/hit then I will take away your PS3 for the rest of the day"
Ask him if he understands, and if he agrees its a good plan. When you are out shopping keep praising him for how well he behaves, how kind he's being to his brother etc. If he starts ot misbehave give him warnings "no, we aren't running over there, you stand by me and help me choose this jumper" If he ignores again, remind him he will miss out on the treat. Finally remind him he will lose his PS3.
This might not be what you are after, but it's how I would have have dealt with my 2 DDs. I really think explaining things before hand, preparing them so they know what is happening to them and acknowledging that you know they dont like it, makes a huge difference to them.