Unable to installworld after successful buildworld and buildkernel

>From $SRCDIR/UPDATING

 To cross-install current onto a separate partition
        --------------------------------------------------
        # In this approach we use a separate partition to hold
        # current's root, 'usr', and 'var' directories.   A partition
        # holding "/", "/usr" and "/var" should be about 2GB in
        # size.

        <make sure you have good level 0 dumps>
        <boot into -stable>
        make buildworld
        make buildkernel KERNCONF=YOUR_KERNEL_HERE
        <maybe newfs current's root partition>
        <mount current's root partition on directory ${CURRENT_ROOT}>
        make installworld DESTDIR=${CURRENT_ROOT}
        make distribution DESTDIR=${CURRENT_ROOT} # if newfs'd
        make installkernel KERNCONF=YOUR_KERNEL_HERE DESTDIR=${CURRENT_ROOT}
        cp /etc/fstab ${CURRENT_ROOT}/etc/fstab                    # if newfs'd
        <edit ${CURRENT_ROOT}/etc/fstab to mount "/" from the correct partition>
        <reboot into current>
        <do a "native" rebuild/install as described in the previous section>
        <maybe install compatibility libraries from ports/misc/compat*>
        <reboot>

This part seems not to have changed so far from RELENG_9 to HEAD.

I failed on "make installworld DESTDIR=/BETA1 |& tee installworld.log"

ERROR: Required unbound user is missing, see /usr/src/UPDATING

How am I supposed to have an unbound user on a partition where there is no existing FreeBSD installation?

Like the job market, where one needs to have two or more years experience, but how to get that first job?

I tried
mergemaster -p -m /BETA1/usr/src -D /BETA1
on thin air, managed to get a master.passwd that included unbound user, but 
make installworld DESTDIR=/BETA1 
failed immediately for lack of unbound user it couldn't find.

I also tried 
make distribution DESTDIR=/BETA1
(and distributeworld too), no joy:
Target directory, either /BETA1/etc or /BETA1/etc/atf, does not exist.

There is a bug in $SRCDIR/UPDATING in the part about cross-installing current onto a separate partition.

I even tried copying /etc directory from USB stick to /BETA1/etc before running mergemaster, but that also failed.

But this was no barrier when I built and installed FreeBSD 9-stable i386 on a USB stick, mounted as /compat/i386.

>From https://wiki.freebsd.org/i386-Wine

# cd /usr/src
# make buildworld TARGET=i386
# make installworld TARGET=i386 DESTDIR=/compat/i386
# make distribution TARGET=i386 DESTDIR=/compat/i386
# mkdir /compat/i386/usr/ports
# mount -t devfs devfs /compat/i386/dev
# mount -t nullfs /usr/ports /compat/i386/usr/ports

but instead of the latter part, after "make distribution ..."
I made buildkernel and installkernel, and booted from the USB stick, used ports directory on hard drive.

That worked, but wouldn't work for FreeBSD-current now due to unbound and /etc problems?

How does one install FreeBSD, building from source, on a partition with no OS installed?

Directories on this partition include /netbsd-HEAD, /pkgsrc, and /usr/src, /usr/ports and /usr/doc.

I use a USB-stick installation of FreeBSD 9.2 prerelease for building FreeBSD-current, but due to a bug in re driver, could not connect to Internet with Realtek 8111E Ethernet on MSI Z77 MPOWER motherboard.

NetBSD-current (6.99.19 updated to 6.99.23) was able to access this Ethernet, so I checked out, by cvs, NetBSD-current source and pkgsrc tree (current, not quarterly), updated NetBSD and packages, and successfully built subversion.

Then I used this svn to checkout FreeBSD-current source tree.

I believe FreeBSD installation would not touch directories /netbsd-HEAD and /pkgsrc.
 
Tom