I was trying the same thing but no success. I installed a calendar in Thunderbird (as add-on) but I cannot synchronize it with the Oracle Calendar. If you found a solution for that please share it . Many thanks.
As fate would have it, I attended a GDS "PC Performance" brown bag the other day here in Rocklin, and they did mention that Oracle is working with the Lightning plugin to have a catered configuration for Oracle Calendar.
So... we can't do it yet, but it's coming soon. This was really good to hear.
We can't use syncml2ical.com for security reasons. Can Oracle help us configure something similar?
Does Oracle really intend to come up with something for Oracle Calendar (standalone in my case)? Or is it Beehive?
Beehive is so far different from Oracle Calendar that it's difficult for large organizations to switch.