Electric Guitar limitations

Hi all, I've been writing some music that has a part for electric guitar, and I'm having some issues concerning playback. Firstly, I needed the electric guitar to be able to play sustained notes. I managed this somewhat by choosing a different soundfont in the mixer (Overdrive Guitar, Distortion Guitar and Feedback Guitar seem to work the best), but I noticed something else: it seems that the sound for the guitar doesn't respond at all to the niente symbol and therefore it makes it difficult to hear what I'm writing, cause a lot of the notes are long, monophonic tones that are supposed to fade in from silence. Any help on achieving a more satisfactory playback would be most welcome, thanks! :)