I was in the simulator the other day and we set the weather at minimums so we went IMC during the vertical climb for an onshore helipad departure departure with a TDP of 35 feet.
We didn't crash but it is is disorientating manoeuvre, particularly during the rotation point and shortly after.
I think this thread has focused a little too much on "rules" and not enough on sensible decision making.
For me it's quite simple, if there is an expectation of going IMC before Vmini then just say no, any employer who doesn't respect the Pilots decisions should not get the benefit of your experience.