Need help for adding graphic to map

[Hitman]

I have created a graphic i want to be displayed in the map like the current nomograph on the right side. I have started from that nomograph data and now the image succesfully displays, but I'm unable to determine how to change its location so that it is placed exactly in the centre of the map screen

Here is the current entry added to my 1024_menu.ini file:

[G31 I59]
Name=Plotter
Type=1030;Static bmp
ItemID=0x3100000f
ParentID=0x31000000
Pos=0,0,200,720
Zone=0 768 200 720 2 1 0x31000000 0.76 -0.02 0x3100000f 0 0 0 0
Color=0xFFFFFFFF
Materials=1
Display=2;Linear
Mat 0=data/menu/gui/layout/Plotter.tga
MatFlags=0x9
TexFmt=0x0

The file is now 200 wide x 720 high, though I might make it 600x600 somewhere in the future to add a graded circle around it. Now what must be changed so it gets centered on screen? Any help wellcomed!