Pre Buffer not working

Hi Jona,im using HTC Wildfire on Android updated to 2.2 and when im driving as soon as i go out of signal my radio stations drop..Even on MPEG stations im using paid version with latest update and ive got buffer and prebuffer on full 60secounds..It doesnt make a difference on my phone if i have buffer and pre buffers on full setting on lowest setting it will always cut out straight away when no signal..Any ideas? Ive tried everything even having both settings half way and still makes no difference...Is the prebuffer meant to work on this phone?