webmail over port 81 issue

[SurfingAlien]

Hi All!!!!!

A number of my users are not able to access webmail (from their work) because they're behind a firewall that does not allow http(s) over port 81.

Is there a way to make this work over the default 443 port?

I know that I probably have to sacrifice the possibility of running https pages on regular websites, but that's ok.

On the other hand, I know that Apache 2.x can be configured to redirect incoming traffic to another URL and maybe even a different port...

Any help would be appreciated!

Regards,
Peter