This is currently not possible, Avion was mainly created for animated textures not constant ones. Once I finish all Avion modules (only Comatlog missing) I may update LibAvion-1.0 and allow triggering each state of an animation, eg. "Show and animate on buffgain" and "Fade on buff loose".
This would be awesome if these event triggers could eventually be added to Avion. While I'm patiently awaiting this possibility I can simply use Power Auras for "static" textures so please take your time =)