I would think that if the insurance was owned by the Plan, and the Plan was the beneficiary, and the defination of Death Benefit did not change, and especially if the insurance was a 3 or 5 year decreasing term policy, it would be ok, and an investment / expense of the Plan, (PS58 costs would also not apply).
If you are looking at whole life, I would have to say why, since you are trying to cover a short term decreasing liability.
Thus can also be done outside the Plan as a key man policy to cover the contigency.