scripts/network/juniper/zone-interface-add.xml

<rpc>
<load-configuration>
<configuration>
<security>        
<zones>            
<security-zone>                
<name>%private-zone-name%</name>                               
<interfaces>                    
<name>%zone-interface-name%</name>                
</interfaces>                
</security-zone>        
</zones>    
</security>
</configuration>
</load-configuration>
</rpc>