mount WebDAV folder as local drive letter

I installed a Web server that supports Web DAV on IIS6, Windows 2003 Service
Pack 2. It is accessible from the Internet, only ports 80 and 443 can pass
through the firewall. Let's call it:
www.mywebdav.com

On the client side:
Windows XP service pack 2, Internet Explorer 7 is installed, WebClient
service is started automatically. I can open My Computer, click Tools, Map
Network Drive, in the Folder field type:
http://www.mywebdav.com/userhome/pub/
or type:
\\www.mywebdav.com\userhome\pub
and then click Finish. This will mount the WebDAV folder as a local drive
letter.

So far so good, this is the desired behaviour and it works. However for
better security I would like to use the secure HTTPS protocol. The server
certificate is trusted on the client computer. Following the same procedure
on the client computer, in the Folder I type:
https://www.mywebdav.com/userhome/pub/

An error is displayed immediately: "The drive cannot be mapped because no
network was found".

Question 1:
Is it possible to mount a local drive letter to
https://www.mywebdav.com/userhome/pub/ over a secure link and how?

I know that I can click "Sign up for online storage or connect to a network
server", Next, "Choose another network location", Next, type:
https://www.mywebdav.com/userhome/pub/
Next, Next, Finish.
This will open the location, but not as a local drive,
+ link is secure
- access seems slower
- cannot be accessed be other programs transparently:
must login from every program separately and every program must support
WebDAV.

Question 2:
What other options do I have?


Thank You for any help!

George Valkov