FokkerWokker,
By vertically, I guess you mean the Formula pane in the bunch of menus down the side?
From memory, Excel for Mac 2008 (I assume you're using this) doesn't show the formula bar by default. You will need to go View > Formula Bar and then drag it where you want it. You can't dock it in the main window of Excel, and yes this is incredibly annoying (used it for years).
Hope this helps.