Delivery level 5, backtrace, and :keep-debug-mode

Hello lispworkers,

I am trying to deliver on level 5 and provide the customer with the
possibility to print backtrace or bug report.

When :keep-debug-mode is T, this works but increases the image size twice as
large as it was when :keep-debug-mode is NIL.

But setting :keep-debug-mode to NIL results in "Undefined function DBG::GRAB-STACK"
in the delivered application. Is it possible to keep the backtrace facility
without TTY mode and without blowing up the image. (Enigmatically coded
symbols do not matter as I can restore their names on my site.)
--
Sincerely,
Dmitriy Ivanov
lisp.ystok.ru