Um Origin likes to mess with that idea alot. I have only managed to get it work with other games. Where you have to start with Origin being off completely. The only other way is to patch crack it but! Then getting a trainer to work might be hard. So keep trying with the first point I mention. It might and might not work at times. I have not worked out a non crack way yet.
Sorry to necro this, but I thought I would add the solution to the question.
Step 1 - Right click the game you want to play and select "Game Properties", then check "Disable Origin in game" Step 2 - Close Origin Step 3 - Go to Steam Library and hit "Add a Game" and then select "Add a Non-Steam Game" Step 4 - Select the Origin exe. Step 5 - (Optional) - Rename Origin to the game of your choice. Step 6 - Hit Play
This will then launch Origin, where you can then launch your game and use the Steam overlay to take screenshots of the gorgeous Crysis 3. Enjoy!
All times are (GMT -08:00) Pacific Time (US & Canada). Current time is 12:53:22 AM