I made an project to control all your somfy screens and shades over wifi / web / android phone.
The app can be found here: https://play.google.com/store/apps/details?id=com.marquesoft.ArduinoSomfyController&feature=search_result.
And the example sketch here: http://db.tt/i9JdVxQb.
This app is ad free!
At first you can set your Arduino ip and port number in the settingsscreen.
When you hit a button i will send a GET request in the following format: "http://yourip:yourport/?string" , "http://192.168.1.120:80/?11". The arduino retrieves the string that comes after the questionmark? and send back a simple html line that will show up in the browser view in on the phone.
To control the screens you connect some relays to your somfy remote as in the pictures below. Some simple soldering on the remote is needed.
I hope you can use this app in you arduino project.
If you have recommandetions or found any bugs please let me know.
When you like it please give it a rating on google play.

Pictures of the somfy remotes connected to the relays:
https://dl.dropboxusercontent.com/u/29369544/Dev/Somfy%20controller%20Pro/2013-10-24%2014.39.01.jpg
https://dl.dropboxusercontent.com/u/29369544/Dev/Somfy%20controller%20Pro/2013-10-24%2014.39.21.jpg