[Samba] shadow:format with random suffix

[Sebastian Gabbert]

Hi,

I want to combine zfs snapshots (via zfSnap) with shadow copys/previous
versions.
So far everything works for me, with one exception:

For simplicity I want to create my rolling snapshots via zfSnap, so the
snapshots are called:
2014-11-28_14.17.00--120s
Here "120s" is the time to live for this snapshot. So everything behind
"--" can vary. I was able to get my snapshots recorgnized via:
shadow:format         = %Y-%m-%d_%H.%M.%S--120s
also
shadow:format         = %Y-%m-%d
works (but doesn't have a valid time, just the date)

But what didn't work is
shadow:format         = %Y-%m-%d_%H.%M.%S
or
shadow:format         = %Y-%m-%d_%H.%M.%S--

Is there any way to tell str[f|p]time to use just the stuff in front of
"--"?

I am using Samba 4.1.13, FreeBSD 10


Thanks and best regards
Sebastian