Art - Caster Help

Hey, I am new here, but i´ve created a lot of custom maps since last year. Now i am trying to creat a new WoW Custom Map, but i have a problem. I have my hero, Warlock, and i wanted to make that green Star surrounded by a circle (when u cast DarkSummonig spell u see it, it´s like Mass Teleport) appear when he casts 1 spell. I use Warcraft Viewer, and founded this star (RepleacebleTextures\Splats\DarkSummonSpecial.blp) but when i put this on Art - Caster... the star doesn´t appear when i cast the spell. Please, how can i make this appear ? I´ve already tryied everything, but no succes...

blp files are images. Art fields, however, are looking for models. I'm not familiar with the effect you're talking about but some model must use that texture to create the effect - that is, it's not a "naked" texture, but rather a model that uses that texture. You're going to want to look for that model that uses the effect, and then use that in the art-caster field.