Using relative URL's fo:external-graphic

Is this possible?  If so, can you give me an example because I cannot
get them to work with my current setup.

Ex:
<fo:external-graphic text-align="right" height="40px" width="78.51px"
src="xml/logo.gif"></fo:external-graphic>
Where xml is a directory underneath the current application context.
The full url would be:
http://myhost/myapp/xml/logo.gif

_________________
Jeremy Nix
Senior Application Developer
Southwest Financial Ltd.
Jeremy.Nix@sfsltd.com
(513) 621-6699 ext 1158