This is a suggestion...
The "Croix du Sud" was the name of the plane of Jean Mermoz "Latécoère 300" ( aéropostale line Dakar / Saint Louis / Rio), the plane on which he died in dec. 1936; may be "MOUKVOS" is a deformation of "MERMOZ" (in african language ? or some other ?)
I don't think that "Croix du Sud" could be linked with the Lorraine cross.