Hanns-G monitors connected thru 5850 video card

I need to know if anyone out there know anything about Hanns-G monitors because I need help. I have three Hanns-G monitors (HH251) in eyefinity mode connected thru my 5850 video card. The monitor that's connected to the HDMI port, I can't strecth the monitor out from corner to corner because the H-Position and V-Position options in the settings on the monitor is grayed out. Funny thing is , the other two monitors ( one connected to the displayport and the other connected to the DVI port) are even and strecthed out from corner to corner but the H and V positon options are grayed out also on those monitors as well. Why are these options grayed out and more importantly, why can't I get the middle monitor to strecth out evenly with the other two monitors so I can have a even uniform setup so I can game with confidence. Please help.