This is a follow-up question to Stephen's Add different materials to different parts of a mesh? As explained there, it is possible to assign different surface materials to different faces of a mesh. However, the same method does not seem to work when the materials involved are not surface materials.
For example, suppose a cube mesh has two materials and both are wire materials. If I assign the second material to everything (enter the Edit Mode, select all vertices [A], select the second material in the Properties panel > Materials tab, and click the Assign button), the cube is still rendered with the first material. I have the same problem with two halo materials.
How do you assign different wire materials to different edges of a mesh? How do you assign different halo materials to different vertices of a mesh?