Hey,
now I can work with XSI (a little bit). I have a questions:

How can I get fire to my model?
Thanks for help!

Why would you want to burn your model? jk

I'm not exactly sure what you're saying, but do you mean you made a weapon and you want it to fire? or do you mean you made some prop and you want to attach or display an effect when it is damaged?
Either way you're going to have to add a hardpoint to your model, for a gun or weapon just place a null at the end of the barrel and name it hp_fire.
For an object/prop that you want an effect to show when damaged or to attach an fx to, just place a null somewhere on the model's topology where you want the fx and name it/them hp_damage, hp_damage2 and so on or hp_effect, hp_effect2 and so on or whatever, then attach an fx to it via ODF with the right code.

Thanks I'll try, I made Revan's Throne, ther are 2 fire pots!

Ok, create 2 nulls, and place them in the pots where you want the fire to come from, and name them something distinguishable.
Most people will name nulls that are ment for effects, hp_emit.