Reployment of Porlet with change to deployment descriptor(portlet.xml) not updating database.

[Peter Cadman]

For example,

If the portlet.xml file references a webservice url and this webservice url is changed, after deployment the preference does not change and still references the original url.

It works if this is the first deployment of the portlet.
We have not changed a property in portlet-ext.properties file that would stop auto deployment of the portlet.

Any ideas where I should be looking.