Rather than quoting figures for the right and left flange distances from the Locknut centerline distance, they quote a "flange to flange" distance, along with an offset, for some mysterious reason.
This image: < should help translate their "Flange to Flange" and offset figures to be right and left flange distances. In the case of this hub, your left and right flange distances are:
Wl = (F.T.F/2 + Offset) = 36.00mm
Wr = (F.T.F/2 - Offset) = 22.40mm
Using the dt swiss calculator, I calculate 292 and 291mm spokes for building a triple-cross wheel with your selected components.