You still need to do the CPL/IR flying training, but you need to sit the ATPL exams, not the CPL exams. This is the way that most people that want to get into the airlines do it in JAR land. The ATPL exams 'superceed' the CPL exams, thats why you don't need to sit the CPL exams.
You could sit the CPL exams, then do the ATPL exams, but there would be no point. It would cost more and take more time, with no advantages, if the airlines are what you are aiming for.
Hope this clears things up.