Ok then i modify my extention to add in-call control volume.
Thank you Taifun for your help.
the only thing i didn't succed to do is to hide UI after few seconds. If i set Show UI to true, it appears on first button tap and desapear only after a new tap on screen...
JmlPhoneCall.aix (7,3 Ko)
Telephone.aia (9,5 Ko)
Mp3Tags.txt (39,5 Ko)