[2] Find the key players. Asking a sales person your engineering question is not the best strategy. You have to get to the engineers somehow. Often it involves no more than hunting down the tech support email address, stating your problem clearly, and asking politely for the help of anyway qualified to do so. I met several very interesting people that way who became interested in the project and did a lot to help me out.
[3] Take a break. Especially when you're coding, but also when trying to solve a design problem. When you get completely stuck, often it's best to just walk away for an hour, a day, or sometimes even a week and let it simmer. Even if it feels like you don't have time, it's worth a try. It lets you clear your mind, and most times I found that when I came back to the problem again, the solution came to mind almost instantly.