As a (maybe positive) side effect I had to separate all PHP classes in a particular directory in order to avoid the tool to get confused with other scripts used to generate Javascript code among other things.
(this post may require some revisions)
grab php2xmi from
http://tech.motion-twin.com/php_php2xmi.html
sample script to run on project directory:
php2xmi \
--no-private \
--no-protected \
--output=/home/rudy/borrame/myresult.xmi \
`find src/class -name "*.php"`
add --path= if you need to include other project files
once you get the XMI file, you can import it with ArgoUML
http://argouml-downloads.tigris.org/argouml-0.34/
it wont generate the UML on the fly
