Corporations helping community or vice versa?

I fully believe that business can be the solution to poverty. The process is simple:
1. Identify the problem
2. Identify the solution (technological, training etc)
3. Innovate to provide the solution to the problem.

Point 2 is actually quite easy, and there are already solutions to almost every development challenge, be it finding water, preventing HIV/AIDs etc. Point number 3 is where the challenge lies. So far government has failed to provide the solution in most developing countries for various reasons (money, ability etc). Can business do better? Well they also need to overcome problems, such as providing the solution cheap enough, ensuring there are qualified people to distribute and provide the solution, ensuring the solution is suitable to local needs and so on.

If a company can do that, great. Companies can profit from helping the community. If they do that, then there is a clear motive for business to invest money in helping raise awareness of the problem, the need for their solution and their proposed solution (possibly through NGO partners).

This is the issue: when does this become unethical? Health companies already understand this uneasy balance when they go to doctors to tell them about their solution to a health problem. This means the doctor will use that product to solve the problem, but is it actually the right or best product -or just the only product the doctor knows about? How to stop the doctor accepting bribes for distributing that product and not another one? Will the patient lose the trust of the doctor knowing how closely associated the doctor is to the company (and companies often havea lack of trust)?

For me, working in an NGO, where we have the trust of the community, we would gladly like to (and already do, to some extent) promote certain products (and sometimes subsidize them) -in fact we are keen to help companies understand the problems and help them develop a solution, but where is the line between promoting something that will help solve a problem and becoming (in effect) a distributor for the company? How does this affect the trust the community has in us, if they link us so closely to a company?