A ver chicos
Es en ingles, pero este es el metodo correcto para que funcione, asi lo tengo y funciona de maravilla
Sonido perfecto tanto tu voz como la de la otra persona
If you doing all from author's instruction you have a problem. There is what I doing for working recorder. So I removed manually througt root explorer hwcallrecorder folder from system/app. After that, restart device. Open settings>programs, from menu select - show system programs(or so) and search for recorder.apk and stop it. Then with root explorer search for com.android.phone.recorder (on all phone - location 'root'). After that delete all this finded files and restart device. After that U make a call and search for call option on menu and it must gone. But recorder button it must be exchanged with callendar. If it is so, the next step. With Root explorer copy (renamed "original" folder from authors link) to system/app. Change folder permissions to 0755 and file inside folder permissions to 0644. Now U have folder named HWCallRecorder with correct permission and file with same name and permission inside it. Thats all. After device restarting U must have working recording menu and button.
P.s. Recorder.apk (from system programs, services etc) need permission to micro.