If you hosting on your Server multiple Websites with you Build-In Mac OS X Apache Server than you can not use the same Port with your Kerio Webservice, but it is often required to use the Standard HTTPS Port because of Firewall Rules. In this Case you have the Possibility to use the Reverse Proxy Feature on your Build-In Apache Server.
First Set Up your Kerio HTTP Server Port to 8080. As next create your Website, something like https://webmail.sf809.de in Server Admin. The Web Folder Path you can ignore. Activate on the Security Pane SSL to use an encrypted Connection, set your Web Server Alias as webmail.sf809.de on the Alias Pane and Jump to the Proxy Pane. There it should looks like my Screenshot:
Save your Settings. After this it should be possible to reach your Webmail via the arranged Website. This works for me in 10.6.2 with Kerio Connect 7.

Mahlzeit
Sehr gelungener Post. Da hat mich Bing mal wieder an einen super Blog geschickt.
Viele Grüße aus Bantai. Petri