If this not work directly with bmp make some simple panel model in MED and then put this panel in model like skin. Now you can use ent_morph for change panels (models). Best thing is when you one time set entity (panel) positions, this work good on all resolution. I use something like this in my game.
If you want use entity istended of panel, you can try next:
ENTITY* car_pan = {
type = "carpanel.mdl";
layer = 5;
flags = SHOW;
VIEW = camera;
pan = 270;
x = 400; // here set your panel position
y = 300;
z = 200;
}
and later when you want change panel:
if (show_car == 1) { ent_morph(car_pan,"carpanel2.mdl"); }
