Maybe someone who flies conventional procedures on daily base whilst relying on his/her G1000 can clear this one out
Or someone with the supplement that can point out the part where it makes clear when you can/can't replace conventional navaids with GPS guidance.
From airbus FCOM:
FMGS lateral and vertical navigation has been certified for after takeoff, en route, and terminal area operations, for instrument approach procedures (except ILS, LOC, LOC-BC, LDA, SDF and MLS), and for missed approach procedures.
Now this is a clear statement of what you can and can not do!
BTW thanks for the help 500, appreciate it!