Unfortunately you can't simply 'move' an icon to the middle. You need to do some fiddling.
Create some blank Folders
ie C:\Users\<YOUR NAME>\Documents\BlanK Toolbar 1 (it doesn't matter where the folder is really)
Unlock the Taskbar
Right Click on the Taskbar > Toolbars > New Toolbar...
Navigate to your blank folder and add it.
Once added, Resize / locate / arrange the new toolbar to push your jumplist icons to the middle.
Right Click on the blank toolbar and Untick 'show text' and 'show title'
Lock the taskbar. Done.