Navigation over davfs very slow with very big files (>1GB) even without preview.

Binary package hint: nautilus

Using Ubuntu 9.04
nautilus:
  Installed: 1:2.26.2-0ubuntu2
  Candidate: 1:2.26.2-0ubuntu2
  Version table:
 *** 1:2.26.2-0ubuntu2 0
        500 http://ftp.tu-chemnitz.de jaunty-updates/main Packages
        100 /var/lib/dpkg/status
     1:2.26.2-0ubuntu1 0
        500 http://ftp.tu-chemnitz.de jaunty/main Packages

The short stroy:
---------------------
There seems to be an issue with nautilus deciding, whether to preview a file or not.
Nautilus should *NOT* display a preview. Settings: "never"
When I navigate to a specific folder, it hangs for minutes and causes some GiB network traffic before showing a 4.4GiB file.

The long story:
--------------------
I connected to a webdav server with mount.davfs over a fast ethernet connection with a few MiB/s throughput.
mc midnight commander is fast navigating through the folders.
nautilus is fast in directories with small files, even previews are okay of small files. (Selectet 'only < 3MiB' in preferences)

I have a directory with one 4.4GiB "dvd.img" file.
When I open that containing directory NAUTILUS HANGS for a minute or two and the network activity goes up to ~90%.
About 1-2GiB of data go down and a few MiB of data go up the eth0 device.
After some time the folder is displayed.
Upon clicking "Refresh" I have to wait again - some GiB download again.

-LATER:-
I changed the filename to "dvd.txt".
I navigate with nautilus to the directory.
The contents get displayed immediately.
The preview if "dvd.txt" is only "..." of course.
But in the background newtwork goes up. Another 700MiB download.
Refresh makes me wait again... :-(
While nautilus hangs, also midnight commander hangs, when accessing the davfs-mounted folder.

-LATER:-
I changed the name to" dvd.jpg".
I navigate with nautilus to the directory.
The contents get displayed immediately.
No real preview, of course. Anyway, it's larger than 3MiB - hence no preview.
No network load! No waiting! :-)
Refresh immediately!

-LATER:-
I changed the name to" dvd".
-> Troubles again... :(
Hanging navigation and GiB network load...

So it must be something with the preview settings.
I guess nautilus tries to download part of the file to determine the type??
This problem might occur with other network protocols aswell.
In the gnome virtual filesystem "ftp://<email address hidden>/users/folder/dvdfolder/" this problem does not appear.

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
ExecutablePath: /usr/bin/nautilus
Package: nautilus 1:2.26.2-0ubuntu2
ProcEnviron:
 LANG=en_IE.UTF-8
 SHELL=/bin/bash
SourcePackage: nautilus
Uname: Linux 2.6.28-18-generic i686