1.60 Mixer problem

Hello I am trying to output some internal drum samples out via the PAD Mixer and The MPC is not letting me select the PAD mixer. I keep getting a message entitled:

Info
There is no DRUM program assigned to OUT1 or OUT2.

Ok I figured out why it was causing me grief kind of.... Now how do I switch between different Program mixers????

So guess I had to switch to the track that had the appropriate program on it. Then hit MIXER cause once you are inside of MIXER mode you cannot change the program which you want to mix???????? Stupid sh*t, anyways I love this machine and try not to complain about it, but things like this really do bother me. Thats not intuitive at all, am I missing something? Also I still do not know why I received the initial error except for the fact that I had a keygroup in Program 1 of my Multi..... appearently once I changed that the problem went away, geezuz christ....

p.s. i don't want to delete the whole topic even though i answered myself cos if any of you have an explaination of why things work that way in mixer mode please feel free. Also I still want to know if there's a way to change the Program once inside Mixer mode without having to backout and trouble shoot.