Hi Paolo
At least there's another italian here !!!
I own a mkII RX300, so I'm afraid I cannot help you (but I've to check the presentation cd-rom included in my car).
You can find a useful tutorial on how to use the satnav (latest versions, but yours should not differ so much) on the US lexus site (www.lexus.com), look for details about RX330 and you should find the link to the tutorial.
Ciao
Mauro