Hello Peter,
Try to give it the full ref name and it should work, e.g.
git push origin refs/heads/master:refs/heads/master
I owe you a beer or two.
(ad027088pc) [~/work/raid_ueberwachung] git push origin refs/heads/master:refs/heads/master
updating 'refs/heads/master'
from 0000000000000000000000000000000000000000
to aca655af03443ef8b4adea269b50471894686b14
Also local refs/remotes/origin/master
Generating pack...
Done counting 18 objects.
Deltifying 18 objects...
100% (18/18) done
Writing 18 objects...
100% (18/18) done
Total 18 (delta 6), reused 0 (delta 0)
refs/heads/master: 0000000000000000000000000000000000000000 -> aca655af03443ef8b4adea269b50471894686b14
Thomas