I have, but BACnet4j doesn't make it straight forward.
First you need to subclass BACnetObject and make a Schedule object class.
In that schedule object class, have a local variable for schedule default property.
In the constructor, set the present value and schedule default properties with this value:
new AmbiguousValue(new ByteQueue(new byte[]{0}))
Then override the get() and set() methods, so that if the schedule default property is being set/retrieved, you get it from your local variable instead of the property map.