The route is described for skiers and takes the same line as the summer route.

Route

From the Finsteraarhorn hut go W to the broad gully (NE) and exit to the left onto the glacier.
Go up N towards Pte 3616m.  At about 3500m, go diagonally to the NW towards a spur which leads up to the SW ridge of the Finteraarhorn.
Carry the skis over the spur, (easy,) then continue to the Hugisattel, (ski depot.)  
Follow the N ridge, either on the crest or on the SW side, to reach the summit.  1-1h30 from the Hugisattel.

Descent

Either: by the same route
Or: by the cwm beneath Pte 3406m shown on the map (identify the day before from the Grünhornlücke) : descend glacier bowl below the Hugisattel, then, instead of traversing downwards towards the SW ridge of the Finsteraarhorn, traverse to the right above a broad serac fall to reach a saddle at the top of a spur.  Cross the spur and descend its left side down a sustained slope, (35 to 40°). The slope opens up before steepening again. (In 2005 the best way was down the centre then on the true right, without difficulty.)  This leads to the  Fiesherfirn,which you go down until the hut.