accessing UpdateManager before the canvas is displayed

My current understanding of the batik threading model is that one can
expect the UpdateManager to be available once gvtRenderingCompleted
has been fired.  This has always worked great for me.  But now I am
trying to "prepare" my canvases in advance by constructing them and
calling setSVGDocument before they are made visible on the screen. I
notice that gvtRenderingCompleted is never fired until the canvas is
made visible in some displayed component.  Is there some workaround
for this?  Would waiting for gvtBuildCompleted suffice, to access the
UpdateManager?

For what it's worth, what I am trying to do here is write a
synchronous version of setSVGDocument- the caller should block until
the doc is fully loaded and ready.  (Yes I am taking care not to block 
the Swing EDT.)
Thanks for your time.