ffmpeg ignore PUT and does POST when sending -f segment chunks

I cannot figure why ffmpeg does send chunck over PUT method when I use the -f dash (parameter) :

ffmpeg -nostats -nostdin -i - -f dash -seg_duration 1 -window_size 10 extra_window_size 2 -remove_at_exit 1 -use_timeline 1 -dash_segment_type webm -c:a libvorbis -b:a 128k -method PUT http://nginx/test/main.mpd

and refuses to PUT (and use POST instead) when I use -f segment :

ffmpeg -i - -vn -acodec copy -f segment -segment_time 5 -method PUT  http://nginx/flux/segment_%3d.mp3

(I need to use the PUT method)