There is actually in Trac no way of docs presentation coming out of VP.
I use a workaround which is quite practical for me:
- make a screenshot of changed diagrams in VP and save them as .png files
copy the image files to a path I defined an Apache webserver Location for in httpd.conf:
<Location /doc> ... </Location>
Alias /doc "//your.local.imagefileserver.org/anysubdir/doc"
then I just use image wiki links to that location in my wiki page, e.g. [[Image(//doc/UML/diagram1.png)]]
This way, after changes to diagrams, I can replace the images on disk without touching the wiki, and the wiki shows the latest on page reload then.