I've done much research on this and at this point, it doesn't seem possible, but I'm hoping someone more knowledgable than myself can help me with a solution. I have a client that needs to sync Outlook calendar with a Wordpress plugin. They need the WP Calendar to display on it's own page and also be on the sidebars, like many existing WP Calendar/Event plugins.
This is what I know:
You can connect a URL based shared calendar to Outlook, but it won't let you edit those calendars in Outlook.
You can publish an Outlook calendar to a WebDav service. But since all the WebDav calendar services I have found, you have to enter in a login/password to access your file. (I tested using Cloudsafe).
I have not found a Wordpress calendar plugin that can access WebDav files.
A possible work around is to sync the Outlook calendar to a Google calendar and then use a Wordpress plugin that will sync with Google calendars. BUT that would mean that each person in the company would have to install an run the Google sync service on their computers, which I'm not sure they are willing to do.
Any suggestions on a way to get this request working? Thanks!