ok sounds good, the script you are looking for would be something like;
dim HS1 as xpBaseObject
scene.GetObjectByName("Headshot1",HS1)
HS1.SetVolatileTextureFile(0,"D:\xxxxxxxx\xxxxxxxxx\xxxxxxx.png")
or to use a material something like;
dim box as xpBaseObject
dim mat as xpMaterial
Scene.GetObjectByName("Quad1", box)
engine.GetMaterialByName("blue", mat)
box.SetMaterial(0, mat)