You add an illumination map texture to the model.
An illumination map is a grey scale image, where white is bright, and black is dark, the whiter the colour the brighter the area illuminates.
For a very basic illumination map, basically take a copy of your texture, highlight the area you want to illuminate, and full it with white, then fill all he rest with black, and save it as nameoftexture_I.dds (that's a capital i not a lowercase L :p ), then when you put the model in the game and set it to highest quality it will be illuminated, you can adjust the illumination with bloom.
(don't use pure black and white because GameGuru gets a bit funny with them, 5,5,5 for black and 250,250,250 for white should work fine).
i5, NV960 2GB, 16GB memory, 2x 2TB Hybrid, Win10.