I have been reading a lot about this feature, but I really don’t know how to do it. I use Busycal and tasks added in Omnifocus should be added in busycal as a task. This should be possible, but how :-)
Preferences > Notifications
Publish due items as calendar alarms:
If you’d like to be notified about due items on a device without OmniFocus but with the ability to subscribe to calendars, you can set up OmniFocus to publish a calendar to your database’s sync server location that you can then subscribe to in any app that supports iCalendar files with an ‘.ics’ extension.
Upon choosing a setting other than Off, a calendar containing alarms corresponding to the due dates of your actions and projects will be created in the same remote sync folder that contains your database. This may take a little while; you can verify that it’s in place (or subscribe to the calendar on your Mac) by clicking Subscribe. The address that appears is the one you’ll want to use when subscribing from other devices as well.