[strongSwan] routing between strongswan clients

[Tito]

I configured and tested the example "Test ikev2/nat-two-rw".  from the 
strongswan web page:
http://www.strongswan.org/uml/testresults43/ikev2/nat-two-rw/

I am able to ping "sun" eth1 interface from "alice" and "venus", which 
works. What i would like to do is ping "alice" from "venus" or "venus" 
from "alince". Something like ping between road warrior clients going 
trough the gateway "sun"! If someone has done this before I would really 
appreciated if he can share to configure "sun" for that purpose.

thank you in advance

Tito