If i'm not mistaken, the copier only supports the "letter" (Lt,Lg,Lt-R,etc.) and the "A" (A4 and A4-R) formats. I haven't seen any with the "B" format to select from and never really looked to be honest with ya

..I know it's not much help but who knows.. But, to make changes stick on display, ya have to press:
Program
Default Settings
Machine Defaults
Cassette Size
Then select which cassette
Then which size paper
I know ya probably already knew that, but just in case.. Good Luck..