Varnish logging and data merging

[pub crawler]

Alright, up and running with Varnish successfully. Quite happy with
Varnish.  Our app servers no longer are failing / overwhelmed.

Here's our new problem...

We have a lot of logging going on in our applications. Logs pages, IP
info, time date, URL parameters, etc.  Since many pages are being
served out of Varnish cache,  they don't get logged by our
application.

How is anyone else out there working around this sort of problem with
an existing application?  Considering a 1x1 graphic file inclusion
into our pages to facilitate logging and ensuring Varnish doesn't
cache it.

Share your ideas.

-Paul