Softimage Xsi: Losing Particles render tree

Hi,


I am losing my particles Billboard everytime I tried to render the scene.


Them I need to recreate the Particle Billbord on the render tree again, and again, and again.....


What am I doing wrong? Is there anyway to keep the Particles Billbord without lose it?


Thks

sorry about the bad english....
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Montana Cyborg
3d character animation and 3d modeling services.