Once the patch is done, just add:

$ grep browse /etc/avahi/avahi-daemon.conf
browse-domains=<mydomainname.org>, local

nb: currently avahi does not support registration of external services, you can add it manually the dns zone of <mydomainname.org>

; services list
_services._dns-sd._udp  IN      PTR     _http._tcp
_services._dns-sd._udp  IN      PTR     _daap._tcp

_daap._tcp              IN      PTR     ed._daap._tcp
ed._daap._tcp           IN      SRV     0 0 3689 ed-server
ed._daap._tcp           IN      TXT     "txtvers=1"
ed-server                 IN      A

_daap._tcp              IN      PTR     bozo._daap._tcp
bozo._daap._tcp         IN      SRV     0 0 3689 bozo-server
bozo._daap._tcp         IN      TXT     "txtvers=1"
bozo-server                 IN      A

nb: filer is on local network

And you will have external + locals daap : rhythmbox and shared daap servers