can GELI wait for da0 to appear in order to load keys from it?

[Lapo Luchini]

Dear Pawel (et al),
  when GELI is used in 'boot mode' (geli init -b), can it wait for the
file system specified in loader.conf to appear?
I have a key on a SD card and it gets probed just after GELI complained
that "Found no key files in loader.conf for ad4s1d"...

I'm trying to load the encrypted devices from loader.conf instead of
rc.conf because there is a ZFS-on-root on these, so they must load
before root mount is attempted... there's also the problem that that is
before fstab is even taken into account, but I (think I) solved that
part of the problem using a (single-sector) partition of that SD card to
hold the key, so I can use da0s2 as a key without mounting anything (as
far as command line "geom attach -p -k /dev/da0s2" goes, it works
perfectly; I wonder if it can work before root, though).

Or any other idea to achieve the same result?
(i.e. having the "as much as possible" on ZFS+GELI)

   Lapo