modify existing sourcecode of android app

Need to modify existing source code of simple audio recording app Currently app can record audio files from internal MIC or from MIC of Bluetooth Headset. Problem which need to be solved: on SAMSUNG phones it does not record audio from BT source and recording it from INTERNAL mic instead of BT. The app is designed to work as service, it does not have user interface and getting all settings from 2 files. Needed to add interface with simple selection of path (directory) to files with settings + reload button which will be reloading this new settings after files selection. + menu for recording settings (4 parameters: bitrate, stereo/mono, time, audio source) The app archiving recorded audio files to ZIP with password protection. It getting the password from file, needs to modify pass-file structure, so the app will be able to get password from different words in 1 file. YOU MUST HAVE REAL SAMSUNG PHONE ON HANDS and BLUETOOTH HEADSET TO TEST THE APP Please no timewasters. If you don't have phone or bt to test the app - DO NOT REPLY.