First of all, recognize that promotions in this economic environment are going to breed more resentment than ever, given the limited opportunities for advancement. And the fact that the job was created for you makes things even tougher. There will be inevitably be questions raised about how you got the position, who created it for you, and what it means for others following a more traditional promotion path.
But you should first try to sort out which people resent you for simple personal reasons of jealousy, and those who are giving you the cold shoulder because they're more concerned about the impact of your new position on their career and organizational turf. For those that are just jealous, you need to accept the reality that some of your work relationships will be lost or at least changed, and that this inevitably happens when you move on. You may regain some of these relationships later, but this won't come about by simply being nice to them. Your best bet to win them over is simply to be successful so that they're compelled to listen to and respect you. So your strategy should be to be open and responsive to your colleagues, but also as focused as possible on results.
For those that seem to be wary of you because of turf issues, you need to figure out how your new role affects the existing power and responsibilities of others. Remember that your new position will likely have changed the landscape for others' opportunities for advancement. So these folks will be intent to maintain their own claims, and resistant to your influence. As a result, you'll need to put up your guard against them and discuss with your allies in the organization how they can help you neutralize and overcome these folks.
In general, your best response is to be clear with others about your new role, and to make sure your boss communicates that to your peers and to other power players in your organization. Particularly when a move upsets the standard organizational structure like yours, it's vital to have clear signals from your bosses about your responsibilities and powers. And then just make sure you do the best job you can and see how your relationships with different people evolve. Good luck.
Read More Power Plays From Ron Brown:
Help! I'm Afraid My Boss Will Block My Job Transfer
Should I Date a Co-Worker?
How Should I Manage a Resentful Colleague?
Help! My Colleague Is Trying To Sabotage Me
Help! My Boss Is Micro-Managing Me!
Send Ron your career and job-related questions.