Author :
URL : http:////docs.vmware.com/en/Site-Recovery-Manager/5.5/com.vmware.srm.install_config.doc/GUID-8C23391...
Topic Name : Connect the Protected and Recovery Sites
Publication Name : Site Recovery Manager Installation and Configuration
Product/Version : Site Recovery Manager/5.5
Question :
SRM 8.1 documentation does not include NAT Support. Old version 5.5 does
5.5 didn't support NAT either (check the link to the 5.5 doc you sent)
8.1 doesn't support NAT either