Grace note and octave line

Is it possible to use octave lines with grace notes? In the example the first two grace notes should go under an 8va symbol. And no, I don’t want to use a work around (playing technique or so).

Have you tried to select the notes, invoke clef popover and write 8va?

Nothing happens.

The clef (octava marking) will display if there are real notes involved… I’m afraid you cannot have this marking only for the first two grace notes.