I PMed you with more infos but maybe you haven't seen it
!
So here goes :
After I saw your tweet that day I did a little Google (Lisa+Soma) and found out this :
http://www.zoeandjohn.com/concerts.html
It seems like they'll perform together (Lisa, Zoe and John) at that festival.
Well that's what I understand from that page : let me know what you think.
