I believe in one interview (its on the net somewhere) when asked how he got started. He mentioned Star and S.T.R.I.P.E. and then said they asked him to do "Day of Judgement" because no one else was wanted to do it. He could be joking of course, but maybe not - since had very little under his belt under the time and suddenly was given the mini-series in which Hal gets made the new Spectre and starring most of the big players of the DCU.