I just had the idea to move sideways while keeping the nose on target using "auto turn to target" and the shkval. Now tis worked quite well, and I tried to get a vikhr shot off, but while doing that I noticed that the vikhr launch reticle was all the way to the left of my nose (I was moving sideways to the left).
So, the solution was to turn the nose of my helicopter to the right, something like 10 degrees past the target.
In short, because I was moving to the left, I had to point my nose to the right of the target.
Now this is odd to me, as I thought those vikhr tubes look in the same direction as the nose of your helicopter and considering the launch velocity of the missile, the sideways velocity of the helicopter should be negligable with respect to the missile flight path.
Is this a bug or am I missing something here?