If you get it to work, thats awesome, but my hopes aren't too high. HL won't even allow you to self-illuminate objects, its very basic shading, practically graphics you see within a 3D application viewport. Therefore, chances are that the material types which produce the shaded trick won't translate properly. At best (if your character is low enough poly already) you can create simple ink lines by cloning an object, adding a push modifier to the clone, and adding a normal modifier (ie: reversing the normals). Make that clone black and you have a basic Ink Line. No shading tho.