[Asterisk-Dev] How to program "Dial an mp3"?

[Satchid]

Dear group members,

I have asked it probably wrongly in the user group, but nobody seems to know
the answer. I am sure someone here is familiar wit this.
Somewhere in this representation:
http://graphics.cs.uni-sb.de/VCORE/Publications/mark_spencer/mark.smil
it is mentioned that one can even "dial an Mp3 file" in *.
Is there anybody who knows how this is programmed? 
When this Mp3 is playing, is it then still possible to receive a call?

Thanks,

Willy