Implementing Bluetooth Dial-up networking(DUN) profile so that mobile device can be used as a wireless dial-up modem for Internet access?

I am trying to write an application which will provide the DUN service on Android so it could be used for Internet access on PC or Laptop. This page BlueTooth DUN says 'application' will play the role of DUN-GW (Gateway).

I guess, the responsibility of the DUN-GW service would be to take data request from Android (initiated by Data Terminal), download the data and provide it to Android for forwarding. Also, it must add an entry, Dial-up networking, to the Bluetooth services provided by Android device (but how?)... And everything else would be taken care of by the OS.

My queries are:

1. How to tell the Android that my application provides BlueTooth DUN-GW service/profile?
2. How would the app get notified that Data Terminal(PC) is trying to connect to the internet through the DUN-GW service?

This has been solved in newer phones.