Dusky Pademelons were exhibited for a while in the Egyptian Temple building at Antwerp Zoo (the building that also holds the elephants and the giraffes). Earlier this year when construction work on the new savannah area started at Antwerp Zoo, they were moved behind the scenes, as the stables in which they were kept are going to be used for hoofed mammals, possibly zebras, in the future (like they were in the past).
During my recent visit to Planckendael, there was some small-scale construction work happening in the koala house - new trees, new soil, new plants, a bit of cleaning, things like that.
It seems likely that the Dusky Pademelons are the ones from Antwerp. Very pleasant new addition, I'd say.