I've done a little reading around the subject, and it would appear to be one of those happy accidents whereby the Elvis estate or whoever didn't want to licence the music to this film, rather than it being an immediate creative choice by Coppola. It's a fortuitous refusal, as I actually think the absence of his music and the presence of other songs ultimately helped the film and gave it new layers of meaning. Anyway, I'm sure you'll find it interesting. Thank you, Mark. :)