I initially posted on Italian forum here (http://www.zeroshell.net/forum/viewtopic.php?p=18921#18921) where REDFIVE posted this answer:
Mmm … this is the italian forum… anyway, if Zs 1 is the default gateway for the network 192.168.18.0/24 , and aws ec2 is the the default gateway for the network 10.0.0.0/24 , add, , on ZS1 a static route ,
10.0.0.0 255.255.255.0 via 194.0.0.2 (but be aware, this is actually a pubblic ip address used as inner ip address of the tunnel) and on aws ec2 , 192.168.10.0 255.255.255.0 via 194.0.0.1…. should work, ….if I haven’t missed something…
Regards