QDBusContext does not work with property methods

I have an object registered with D-Bus, which derives from QDBusContext and exposes some Q_PROPERTY on the bus. D-Bus provides an implementation of the org.freedesktop.DBus.Properties interface, so that these properties are transparently exposed to D-Bus clients.

However, inside the getter and setter methods of this properties, QDBusContext::calledFromDBus() returns false.

This makes it impossible to:

1. Return a D-Bus error (in case the property is set to an invalid value)
2. Know who the caller was (in case I want to return a different value depending on how privileged the caller is).