Interaction of WebDAV with HTTPS and problems opening files

Hi,

I have WebDAV setup on a linux apache server with HTTPS.  I am 
encountering a strange situation which is that I can map the WebDAV 
folders onto a Windows computer and then view and copy files from that 
web folder onto the local system, but I cannot directly open the files. 
  The "open" option does not exist, and double clicking does nothing. 
Dragging and dropping files or CTRL-C/CTRL-V (copying them to the local 
system) works fine and then the files can be opened.

Is anyone aware of the cause of this problem?

Also, the same system does not seem to allow me to connect to the WebDAV 
folders via HTTP.  The same username/password which works for the HTTPS 
version is rejected by the HTTP connection.

TIA,

Ian

-- 
Ian Stokes-Rees                 i.stokes-rees@physics.ox.ac.uk
Particle Physics, Oxford        http://www-pnp.physics.ox.ac.uk/~stokes