Videocards - AMD - ATI AMD Radeon graphics cards. Do you have one or want to buy one? Use this forum to discuss anything concerning products using Radeon graphics cards, CrossFireX, from Radeon 9800 to HD 6900
You can try adding 1920x1200 through CCC to the 19x10 screen, but there's no guarantee it'll work. Other than that, I don't think it's possible. You might want to consider setting your resolution to 19x10 on the 19x12 and set the digital scaling to centered if it's really that big of an issue.
Why use cloned mode anyway? Seems like a waste of desktop space if you ask me.