Resident permit do I have to legalize all documents again ?

I have been a belgium resident for 8 months now and i applied for my 13 year old son since the 25th of january and he got denied on the 25th of april. Although i am yet to receive the returning documents but my question is if i will have to legalize again all the documents i had legalized and submitted before for the refused applIcation or its still valid for a new re-application. thanks