You can't create culture with edicts, culture is an emergent property of the community that either is supported or fought by the power structure at hand. A corporation is like an ecosystem, you can create the conditions that will allow a healthier culture to flourish but it will likely take a huge amount of time for that culture to take hold, assuming that there aren't other roadblocks still in the way such as entrenched middle management with different ideas about the place they want to work.