Ok, Antartica, I gotta say something here. You have a full machine shop in the barn ... (enviable by most on this site) ... but no m5 tap on hand? the m5 is one of the most useful taps if you end up doing saw work. m6 and m4 are close seconds. I think its m5x.8 that you need. Even the harbor freight metric tap set should have one of these, and I can't imagine that'd cost you more than $40 for the whole set. of course, thats one of the first ones that I broke myself, ... or had to create a flat bottom tap... i forget, so eventually you'll need a bunch more m5's.
Though it seems like this is kinda a dumb thing for them to miss, the reality is that its far easier to find a tap and tap it yourself than to fight with hutzl over this. AND, the no threads issue is a FAR easier fix than some of the other issues people have had. Consider yourself fortunate.