Are subscribed task and event calendars readonly?

Are subscribed task and event calendars readonly?

We are currently evaluating whether or not to use Zoho versus TeamBox, Basecamp, Box.net, or 5pm.  I am little annoyed that it has been a day since I submitted technical support a question.  Doesnt bode well for our confidence that Zoho is a viable solution.

While we have exercised most of the functionality, the one thing I am not able to do is to get the subscribed tasks working two-way.  I can see the tasks and events nicely in both Lightening and iCal, but in both clients, the calendars are marked read-only.  I have not been able to figure out how to make the task and events writable.

I hope this is just some confusion on my part.  If the tasks and events are not updatable or writable from the client, this suddenly becomes pretty worthless.

Thanks,
Bryan