iOSToolbar.Insert
From Xojo Documentation
Method
Inserts the BarButton at the specified index (0-based) on the bar.
Sample Code
Insert a button in the first position of the toolbar:
Toolbar.Insert(0, iOSToolButton.NewPlain("Save"))
Inserts the BarButton at the specified index (0-based) on the bar.
Insert a button in the first position of the toolbar: