Hello,

I am currently using an SDK an Adobe Flash Builder to build an own Android mobile application. I am doing it according to the following site: http://www.voip-sip-sdk.com/p_456-vo...tion-voip.html
The site also provides code snippets that handle the physical buttons and the rotation features of the mobile devices. The SDK is in C#.Net but there are various examples in VB.Net, ASP.Net etc.
Hope I could help you.