Minecraft X-box 360: Why am I unable to activate an End Portal I created?

I have the latest version on Minecraft on my X-box 360 (as of December 2013). While in creative mode I have tried numerous times to create and activate an End Portal with nothing happening. I tried removing one block and replacing it, I've tried creating it one block above the ground, and Iv also tried searching the internet for hours (including the Minecraft forums) with no luck in finding a reason for this problem. I watched videos online to make sure I was building it correctly, and I even found an End Portal in a stronghold that i was able to activate and go through… Yet when I build one myself, I can't get anything to happen at all.

If anyone has even the slightest idea on how I could fix this issue, I would really appreciate it. I'm currently building a map from scratch that I intend to play with friend as a long adventure to reach The End. Unfortunately I can't finish it without an End Portal to take us there… Lol.

If you're building in Creative mode, you have to be standing inside the portal when you place your last Eye of Ender on the portal frame. It should instantly take you to the End.