Current;y we are plagued with this bug in the extension.
[ 1760207 ] Async Calendar Providers don't work
Code:
Asynchronously working calendar providers (e.g. Google, WCAP) don't work,
because the current code relies on calICalendar::getItems return *after*
the results have been notified, see
<http://sync4jmozilla.cvs.sourceforge.net/sync4jmozilla/funambol-mozilla-pl
ugin/syncmlcomponent/src/c%2B%2B/CalItemsCollector.cpp?view=markup>
line 177 and following
Callers of calICalendar::getItems must expect the call to immediately
return. calIOperationListener::onOperationComplete finally signals that all
data has been retrieved (and notified via
calIOperationListener::onGetResult).
I know remote calendars work with the ScheduleWorld extension.