Writing a grace for public school grad, trying to keep non-denominational.?

My friend and I were asked to write a grace for our grad a few weeks ago. We are buddhists, and we really tried to keep the grace non-denominational. We made no mention of god, just asked people to give thanks to those and that which they love. When we handed in the copy to our vice principal, she rejected it. We had a meeting with a Christian teacher who gave us some ideas on what we could do differently. He suggested we use the term "God" because it was non-denominational, and many different religions have their own gods. He also suggest we end the grace with "Amen", a term he also felt was non-denominational. We now realize we cannot please everyone and don't know what to do. We feel it would be best to resign, because we cannot do it our way and if we do it how they want us to, we will not seem sincere. What should we do and do you think it is fair for us to say god and amen at a public school?