Here is an example of the two #SECRTT macro statements that can be used to secure all TASKS except task code DMLO internally, with task DMLO secured externally.
NOTE: The EXTCLS and EXTNAME parms must be on the TYPE=ENTRY statement.
#SECRTT TYPE=ENTRY,RESTYPE=TASK,SECBY=INT,EXTCLS='OTRAN', X
EXTNAME=(RESNAME)
#SECRTT TYPE=OCCUR,RESTYPE=TASK,SECBY=EXT,RESNAME='DMLO'