I can not use "nat.uac" and "nat.uas" as registrar flags:
0(12872) str2s: ERROR: unexpected char N in NATuac 0(12872) set_mod_param_regex: 'registrar' matches module 'registrar' 0(12872) find_param_export: found <load_nat_flag> in module registrar [/usr/local/lib/ser/modules/registrar.so] 0(12872) set_mod_param_regex: found <load_nat_flag> in module registrar [/usr/local/lib/ser/modules/registrar.so] 0(12872) str2s: ERROR: unexpected char N in NATuas