Forward call from Twilio SIP Registration to the dialed number.
Deploy with:
google_appengine/appcfg.py -A PROJECT-ID -V v1 update twilio-call-dialed-number/
In the Twilio console go to Programmable Voice -> SIP Domains -> {domain}.sip.twilio.com and set the GET Request URL with:
http://<YOUR_PROJECT_ID>.appspot.com/forward?callerid=CALLER-ID
That's it, it should work.
If you do not wish to to host this script on your own account, you can use my hosted script. However I do not garantee its availability and its stability.
https://twilio-1380.appspot.com/forward?callerid=CALLER-ID
Enjoy your calls :)