transposing treble clef to bass clef

I'm trying to transpose a treble clef piece into bass clef. I have tried dragging the bass clef to the treble clef at the beginning of the piece and I've tried clicking on the first measure and double clicking on the bass clef sign. It will transpose the notes, but not the key and it leaves the treble clef sign at the beginning, but puts the bass clef sign for all the remaining staves. See attached file.