Building image for Routerstation Pro

[Ain]

Hello!

I am trying get big picture, what is needed to make standalone, all in
onboard flash installation. I found some good pointers, like Adrian Chadd
patched utilities and README at http://people.freebsd.org/~adrian/rspro/
But something seems to missing, from example, i don't get, why  mfs writes
mdroot in kernel and then  mkfwimage (used by mkflash script) combines new
kernel with mdroot file again.
Second thing is (if i understand correctly) 13 MB is allowed RSPRO image
size.
My  temporary file system image size is 13-14 MB (created by  Adrian mfs
script, named /tmp/mfsroot).
mkfwimage raports  combined image filesize 19MB (i added little printing
statement in create_image_layout, before if (filelength(rootfsfile) +
kernel->partition_length > p->firmware_max_length) ).
What is needed to make system smaller? Sources are 8. june CURRENT, kernel
options MD_ROOT_SIZE=8192

Any pointers or questions are welcomed,

Ain