Have MS Office to work with Jack Rabbit WebDAV
The solution given below is for internal usage only. Do not follow if you're not realize what you're exactly doing.
There is well known feature of MS Office which prevents it from correct work with WebDAV. During transmissions back and forth MS Office magically lose important auth headers which actually imply on WebDAV security. After hours of struggling with this, the only solution for internal usage was to disable authorization in Jack Rabbit.
I tried to play with security settings in jack rabbit but wasn't successful. The reason is that by default anonymous user has read only permission and any other login has full permission. I was able to tweak file:
SimpleAccessManager.java, rebuild sources and everything got worked :)