You need to use a command line function on the shortcut icon.
Right click on the icon you use to run the game and select properties. On the shortcut tab there will be a box labelled Target which will contain the location of the FM2007 program eg mine says:
C:GamesFM2007fm.exe
Now to that box you need to add two commands;
--fullscreen_height=N
replacing N with the desired height and
--fullscreen_width=N
again replacing N with the desired width. (There are
two dashes at the start of each command.)
For example my shortcut now reads:
C:GamesFM2007fm.exe --fullscreen_height=1200 --fullscreen_width=1920
(Dell 2407FPW :D )
You might find the first few splash screens are surrounded by a border but once you get to load game screen evrything will be OK. Be warned the fonts may look very small but the pitch will be the correct ratio, (it'll have extra space behind the goals.)