Finder webdav problem

Hi all,

i've set up a webdav share on a FreeBsd 8.2 machine with apache 2.2.21. I have some problem with Finder (client):

i can create and delete files but sometimes files disappear in finder. If i cd with terminal in folder the ls command show me all files

The share is available for many user (different mac but same OS 10.7.3), I've follw this guide but no results http://support.apple.com/kb/HT1629

What could be the problem?

I run Mac OS 10.7.3.