At the risk of misleading you, I think you open the top and then hold the "OK" button down until the carriage moves over to the left.
I hope that the B9180 experts with chime in, correct me as necessary, and give you the correct scoop on this.
FWIW, I've just abandoned my B9180 and bought an Epson R3000. No regrets, just time to move on rather than spending my time chasing one work around after another.
Ciao,
Doug