Forming terrestrial planets around a pulsar

From the arXiv, a paper on the formation of the terrestrial planets in the PSR B1257+12 system (which is of course the system that contains the first confirmed extrasolar planet, the first confirmed extrasolar terrestrial-mass planets, the lowest mass extrasolar planet currently known, and was the first confirmed extrasolar multiplanet system, but despite all this has received little attention since its discovery... I'd guess fusion chauvinism). The Pulsar Planets: A Test Case of Terrestrial Planet Assembly

Suggests that the supernova fallback disc is the most likely scenario for the formation of the planets, rather than a disc formed by the tidal disruption of a companion to the pulsar (the latter explanation would concurrently explain why the pulsar is a millisecond pulsar, but apparently it doesn't work nearly so well at forming the planets at their observed masses and separations). Interestingly the pulsar seems to be of fairly recent origin, unlike the majority of millisecond pulsars. Strange.