dglshrn-
That's the gist (before then continuing, to drill the front side of the fork) but also an oversimplified explanation.
The screw is surrounded by adhesive, and if there was a head to use for purchase with a tool, you'd damage it when drilling anyway (I should probably have called it a 'bolt' or 'piece of threaded bar' instead of screw).
Look inside the steerer from the crown and you'll see the screw running through the filled brake hole (probably covered in excess structural adhesive and a bit of paint).
Once the rear half is drilled, ideally, you should remove the remainder of the steel screw before attempting to drill the front (because the harder steel will cause the drill bit to wander off its course into the softer alu crown, and probably result in the finished hole being in a dangerous position at the front.
I've drilled two of these forks, and both times I started at the rear, then tried to work the screw loose, using pliers, gripped from under the crown.
On the first occasion, the above method was successful, and I was able to drill most of the way through (from the back), before finishing the hole from the front so not to chip the paint. The second time, the screw wouldn't budge after drilling out from the rear, so I then chose to drill from the front, from a marked centrepoint on the little raised flat bit where you expect the brake hole to be. However, the front and rear holes didn't line up 100%, because the drill had wandered slightly off course due to the steel screw as described above. This meant that I needed to ovalise both the holes slightly, with a round file, in order for the brake caliper to fit correctly. Was a bit of a faff but got there in the end (phrase sums up this comment).Bottom line: if you're at all unsure or aren't confident using the tools, don't bother. Dolan would also concur it's not a good idea to follow DIY advice from some guy on an internet forum when modifying their product.
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Lukas
They certainly are drillable. Best done clamped firmly under a pillar drill, by someone who knows what they're doing (i.e. not your LBS).
There's a steel screw glued inside the (aluminium) crown of the fork, that fills the brake hole. It has been covered with filler by the factory, before painting.