executing onto what desktop?

[Gumbel]

Hello,

I'm having a little problem with my blackbox and geometry. I use several
workspaces and I would like to start for example emacs on my second
workspace. With other windows managers I have heard you can do this my
setting extreme values with the -geometry flag, since some window
managers uses one huge workspace and divide it up. BUT blackbox doesn't
work this way so now I'm stuck.

Question: How do I execute a program onto an other workspace than the
active one?

        Thanks, joh