vestax tr-1 traktor pro mac 4 decks mapping

hi,
I just bought a vestax tr-1 which is just awesome!
i just have this problem:
the default mapping is aimed at using 4 decks with volume faders and pitch for 2 decks and then switch for the 2 other ones.
actually i want to change the 2 pitch faders to volume faders for deck c and d so i can control them on every position of the deck's switch.
so i change the mappings by "learn"but it appears that it doesnt work out the fader doesnt follow smoothly but jumps up and down!
then i try to manually input another midi entry:ch10pitchbend is the name of the note, then i have to tick the invert box and it works(i just cant use both c and d faders at the same time)
then my biggest problem is tha even saving my mapping, if i quit traktor and lauch it again the mapping has disappeared!
if somebody can help me i would be enchanted!thanks!