Spec and bump maps?

Hope this question has not been answered before; While trying to paint the MD11 I noticed that there are native bump and spec maps for fuselage, tail, etc. but I couldn't find any for the engine textures. Is it possible to add those textures by mayself, or has this to be coded into the model?Thanks for your help.Tobias

Edited February 6, 201214 yr by Tobei