i have not done this yet, bu effectively what i believe you have to do is the same as anyother dumpvalve installment, you need a source of vaccume, which can be from a T piece off a vaccume hose, or as i understant it there is a nipple on the underside of the inlet manifold that the standard n249 gets its vaccume from i will be simply joinin one piece of 3 mm blue vaccume hose from the top of my dv, to the nipple, no T pieces or joins.
in my opinion this is correct but like i said i have not done this yet, also i belive once the n249 has been bi-passed, you can unplug and completely remove the valve, to tidy things up, not sure if any faults will show tho?? please correct me if im wrong but thats what i was shown in an illustration