Interesting concept, this transfer of slots - especially here in Europe. I suspect that Sabena's transfer of them to DAT is illegal on a couple of counts: (1) they don't belong to the company, but rather to the airport/government concerned; and (2) if they do belong to the company then they are an asset which should be sold off to the highest bidder for the benefit of Sabena's many creditors.
I hear that both EZY and FR have already commenced action against the 'new' Sabena - claiming (with some merit) that it's really state funded and therefore illegal. Apparently, the banks concerned have been given 100% government guarantees for their loans. If correct, it tends to show that the new business plan is not exactly commercially viable!