OKI 16n printer with 2nd bin access problems

Problem:

OKI 16n with optional 2nd Tray.  Tray 1 has letter headed, Tray 2 has
plain paper.

When printing from the first bin and then the second, all is fine, by
changing pages 2 and onward to reflect the 2nd tray (Format, Page, Page
Setup - 2nd page type set up for 2nd bin).  This satisfies printing
(say) a three page letter with the first page being a letter headed page
and subsequent pages plain paper.

However occasionally a copy print is required, or simply a plain paper
memo.  Access to the second bin first causes the printer to require
manual input.  This is obviously impractical for mass letter printing.

Anyone out there with a solution?

Thanks in advance.

Please reply to gswee @netcomuk.co.uk