SoftEther VPN's L3-switch is worked for virtual hubs(L2-switches) running on vpnserver.
if you require non NAT(IP-masquerade) routing, you need create a tap device(linux) or virtual NIC(windows) on your vps. then you must set proper iptables etc.
Paravirtualization use of tap may be limited by vps provider. in this case, SecureNAT(virtual NAT) of SoftEther VPN is available.