we just bought spa8800 series gateway 4fxs with 4 fxo port. And found there is no option to set NAT mapping enable "No" however does allow to set for Phone 1 but for other lines its "Yes" by default and does not allow to set.
We did try to disable by provisioning method:(using .cfg)
Added NAT Mapping Enable "no" (parameter) under phone 1 2 3
but as soon as SPC tool compile .txt file to .cfg its prompt error " unknown parameter found"
Please do let us know if can be solved.