You cannot modify the LabVIEW toolbar except to turn it off. The only
ways I know of to create your own is to use Booleans with custom icons
and a decoration as a background or use an ActiveX control (i.e
Microsoft Toolbar). If you use either, snug it up against the LabVIEW
toolbar and have the LV toolbar turned off when running, the custom
toolbar will appear in place of the LV one. You would also have to
turn scrolling off because otherwise the custom toolbar would scoll on
the front panel along with other front panel objects.