I think you miss the inside policy from zone untrust to zone trust:
set security policies from zone untrust to zone trust policy pol_NAS match source-address any
set security policies from zone untrust to zone trust policy pol_NAS match destination-address 192.168.5.160
set security policies from zone untrust to zone trust policy pol_NAS match application 51413
set security policies from zone untrust to zone trust policy pol_NAS then permit