Coincidentally I just read an interesting Australian article that claims that "if it's not done properly, engine-failure-after-take-off training can be more dangerous than the real thing"!
Check out
www.flightsafety.org.au/articles/e0051.php
My advice - before the revalidation flight agree with the FI/examiner that should he want you to shut down in-flight, you will talk him through the procedure in real time (i.e. touch the appropriate controls, etc.), but not actually do it. Can't see anyone having a problem with that.