Automation, only one instance

I am going to write a little application with automation support
(ATL ActiveX Automation Object).
If I start my Testapplication from Visual Basic,
there will always be a new Instance of my application.
"CreateObject("blabla.blabla")"

How can I manage that there is only one
instance AND all VB'scripts and other clients of
my app can call Methods on the one and only
instance ?
Thanks a lot for your answer.