I'll point out that in the Genero 3.10 EAP which is currently running there are two new RESTful Web Service demos/examples as well.
The key with most RESTful Web Services is understanding the API, and from that determining what 4gl methods are appropriate. So if I take for an example a page like
http://docs.developer.amazonservices.com/en_US/feeds/Feeds_SubmitFeed.html you will see some switches that allow you to Show/Hide example code, use these as a guide. Also look to see if there is a test area/sandbox you can test on.
If you have not done any RESTful Web Services I would suggest working closely with your local support centre to get the first API done. Once you have done one, the second, third will be easier.
Reuben