My co-workers and I (at a Bernina dealership), have decided the best way to piece on a Bernina with the 9mm needle plate hole is to use a #34D foot and move the needle over 3 bumps to the right. Then your fabric is engaged with both feed dogs. With any of the 1/4" feet, the right feed dog does not engage with the fabric (thus the piecing problem). With the needle bumped over 3 to the right, you guide your fabric just inside of the right feed dog. Works perfectly!