Any carbide milling cutter will work fine in HSS. Here's an involute shape milled on the end of a 1/4" HSS toolbit prior to using it to cut an internal gear:

The cutter is a 3 flute uncoated carbide slotdrill. Similar to turning hardened steel use reasonably high surface speeds, shallow DOC and high feedrate. Ideally the shear zone should be red hot as that will soften the steel where it is being cut, but leave the bulk of the material hard.
Andrew