Xvfb: enabling the composite

[Irek Szczesniak]

When I run Xvfb this way:
Xvfb +extension Composite :1

I get the composite extension available in Xvfb, but the windows of 
any application are not redirected to the off screen storage.  In 
order to redirect them I need to run some application which would do this:

XCompositeRedirectSubwindows (s.dpy, s.root, CompositeRedirectAutomatic);

Is there perhaps some command line switch of Xvfb which would enable 
the redirection?  For instance the backing store has those switches: 
+bs -wm.

Thanks for reading.


Best,
Irek