Hello:
Well well... Maybe, if your customer field is 5 character namespace such has "HJDTS" for example, you could try:
TABLEP0002
NUM=BHJDTS
or with operation VARGBHJDTS after TABLE operation.
Either way you could fetch de value of the date; but you still have to compute it again payroll period.
Eventually you could need to setup a customer payroll operation for this.
Good luck.
Antoine