Non-spouse beneficiary required begin date

[BCGEA]

DB plan's pre-retirement death benefit for unmarried participant who dies with vested benefit prior to age 60 is life annuity payable to beneficiary starting when participant would have attained age 60. How does this work with 401(a)(9) regs that require the life annuity to the beneficiary to begin within year of death (no lump sum available)?  If the participant dies at age 50, by when does the non-spouse beneficiary have to take the benefit? 

[SoCalActuary]

You should not violate the plan terms, so I suggest you find the plan's annuity start date and amount payable, then treat the non-spouse beneficiary as a deferred vested participant.