I'm right in there with Crockett, I tried the black lacquer primer with the same results... cracking over most of the fuselage after a day or two, I even let mine sit about two weeks before I used the Alclad on it. After the cracks I went back about 5 months later and tried it on some areas I hit yet and still didn't like the results. (believe it or not, the gloss black still felt tacky after that long)
I use the same method as him now, polish the plastic nice and shiny with progressive grit sandpaper (I also use those nail board, the medium and fine will get the plastic like glass!) then a few light coats of future until I build up a glass like surface. Let that cure a few days and BAM!!! You're painting the Alclad like a pro.. (sound effects thrown in to add drama to story)