I tried on LIVE 9 but that should work on Live 8
Insert a midi track
Insert a midi clip (click right on the first scene)
In the clip view at the bottom, you got the Bank, Sub and PGM change in the notes window.
You just need to drag up or down on PGM to select the right pattern.
You can add a scene, add a midi clip and then put another PGM on the same track.
There is one problem with the A4, it does not change the pattern immediately even if you setup the program change to immediate on the A4. Sounds like a bug to me.