Im trying to get a a little android app to work to sync my briefcase

Downloads from the Zimbrahost work fine - any size - any number
but uploading is a mess

Everyfile above 1.5 MB result in a broken pipe message on the phone side
sometimes it work s(1 out of 25 or so for files up to 2.5 mb) but usually it doenst

its also not a timeout thing - im trying to upload vom a 2 mbit line so a 2 meg file should take about 10 sec

funnything is that the same libary/wrapper work fine on other webdav server but only zimbra do the problems

however in theory it should work wihtout https (android sdk bug) but thi isnt an option - nothing without https

so anyone any idea/ suggestion / similar expierence

btw: netdrive cleint for windows with webdav is absolute no issue
100% perfectly weirdo thing