Multisite shared ssl – wrong links

I use wordpress 3.5.1 and the https plugin 3.3.6
I activated a network with 2 sites

example.com
example.com/en

Because of scarcity of IPv4 adresses I setup a shared ssl host on the same server. example.net is ssl proxy for example.com

<Location /example.com>
        ProxyPass http://example.com
        ProxyPassReverse http://example.com
</Location>

This should work:
https://example.net/example.com
https://example.net/example.com/en

in the database wordpress-https_ssl_host is set to

https://example.net/example.com/
https://example.net/example.com/en

When I log into https://example.net/example.com/wp-admin first all is working, specifically the “My sites” links in the left upper corner are correct

https://example.net/example.com/wp-admin/network/
https://example.net/example.com/wp-admin/
https://example.net/example.com/en/wp-admin/

when I click the last link (with the en/wp-admin/) the links are turning into

https://example.net/wp-admin/network/
https://example.net/wp-admin/
https://example.net/example.com/en/wp-admin/

You noticed that the last link is correct but the first 2 links has stripped away the example.com/ stuff. Other links are missing the example.com/ too now.

Is the https plugin doing wrong?
Is something wrong with my setup?
How to find out?

I would be glad for some help.

http://wordpress.org/extend/plugins/wordpress-https/