On the X10 that was accessed by pressing the AF button on the left side. On the pics of the X20 that button has been replaced by, well, a button with a camera icon. The Trash/Drive function on the 4-way controller is now Trash/AF.
Am I correct in assuming the function is still there but has just moved to the 4-way controller?
I should add that I don't own an X10, but am considering an X20.
You are correct.