Assigning aftertouch to introduce lfo/vibrato

High, big fan of key groups, most if not all of my custom ones load fine on non beta firmware albeit in legacy mode (fair enough) Most of them have vibrato/lfo set to the mod wheel control but as soon as I switch off legacy the vibrato on wheel stops working, I have figured out how to go into lfo settings and get it back fine.
What I want is to be able to assign aftertouch to trigger the modulation/vibrato in the matrix but nothing I have tried works what am I missing please?
I am setting channel pressure as the source, destination as lfo1 apply aftertouch has no effect although mod wheel works so I know I have applied the lfo correctly

I tried this just now and it works for me.
I specified Channel Pressure as Source in the Mod Matrix and LFO 1 Level as Target.
Then on the LFO page I adjusted the Rate to taste, turned down Level (otherwise it would be on all the time) and on the Destinations page of the LFO I adjusted To Pitch to taste (20 in my case) and got a nice vibrato once I played my keyboard and applied some pressure.

Thank you that was pretty much what I was doing but your response made me look closer and the level and amount to wheel makes a difference, thank you now MPC keygoups are perfect thats exactly what I have been waiting for and hoping in the new software.

Great you got it to work.