Capture audio from microphone, encode and save to wav file

I've already seen this Si开发者_StackOverflow中文版lverlight sample (from Andrej) on audio stream capturing from a microphone and then with possibility to save it to the wav file. It works ok.

But can anybody help me how to modify this sample and build-in NSpeex encoding with saving encoded audio file to local disk?

Many thanks in advance!

Matjaz