I am trying to convert a Platinum Load job into a IBM load. The Platinum control cards have the following

D_ACT_SCHED_599 DATE EXTERNAL
NULLIF ESQL (D_ACT_SCHED_599 = '??????????') OR
(D_ACT_SCHED_599 = ' ');

I cannot get to work in the IBM LOAD. Has anyone used a OR in the IBM NULLIF syntax?