The way this is worded I don't actually understand what happened, and how your choice was an ethical dilemma. There are many times when managers choose not to tell someone below about something. This isn't actually integrity and ethics, it's just a choice that managers have to make in certain situations.
An example of an ethical dilemma would be in regards to a manager asking you to do something that you didn't believe was ethical. For example, you have to collect 100 surveys, and instead of randomly collecting them your boss asked you to find as many of your friends to fill them out to make it easier. What do you do?
Integrity would be what you chose to do. Its the meeting of your morals and your choices. Did you do what your boss told you, or did you decide to work overtime and collect the 100 samples from random individuals as the client asked.
I'm not sure if your decission was really that tough. But maybe if you could word it differently, and help us understand how this was an ethical dilemma and how you did/didn't maintain integrity it would really help. Get back to me