pass rendering names Tweet

[HHbomb]

Hi, I just tried for the first time to render animation with Light pass.
Is there a way to have an underscore ("_") sign after name pass (before numbering) as for example for "Light pass 3" I get 'RENDER__Light pass 30000.tga" and "Light pass 2" I get "'RENDER__Light pass 20000.tga" for first frame.
I would like "'RENDER__Light pass 3_0000.tga" and "'RENDER__Light pass 2_0000.tga"
I could batch rename but I would like a direct cool naming.
Is it possible in Max ? Or this is a Octane problem ? Thanks