HELP HELP HELP (2)

Hey guys,
now that i have your attention maybe someone can help me.
I remember being able to command line render in the background from a prompt while i still was able to launch soft3d in the foreground and work (granted i could not render
with the mental ray renderer) but i could still model in a soft
session. i have not been able to get this to work with xsi, if i have xsi open i am unable to run xsibatch it just skips each render. i am able to have soft3d and xsi open at the same time but i would really like to continue to model and animate in xsi while batch rendering in the bg. anyone have any luck with this or do i have to by yet another seat of xsi.

thanks for any info
Bob