You can have sub macros <macros name="voicemail"><macro ...> and allow you to call it login@voicemail.
Change the sound-path to sound-prefix to make it constistant with the rest of freeswitch.
Also allow to set a sound-prefix to a macros, so you can override it for a specific file set.
You can set say-modules="en" or whatever in the <language section to define that say module to use.
Marc Olivier Chouinard