Finally with the help of the above link I created an example weather report, that the GXV3000 understands:
<weatherreport time="2009-04-10 20:22:17">
I do think we can leave the second forecast-entry out.
Cloudy gives a nice picture. Sunny also. I haven\'t tried other weather types. So any help is apprectiated.
You can serve the xml file directly to the GXV3000 from an http-server like apache.
For a more dynamic approach you have to do of course some programming. Because I am more in to Java than
PHP I think to write a servlet served by tomcat.
Hope this is helpful.