Stepchildren dependent passes (Nairobi)

We are scheduled to move to Nairobi January 1st Protected content permit for mother in process) but have just found out that if my stepchildren are not adopted by me, they cannot come with my husband and I. He has custody of the 2 children and I support them but they are not considered my legal dependants without adoption.
Does anyone have any experience of getting stepchildren into Nairobi?