Hello,
If WiTopia is providing only client to gateway VPN, where WiTopia is the gateway allowing connections to clients, than you will not be able to configure RV120 to connect to it. RV120 in its VPN configurations cannot be configured to be a client.
The only tunnel where can play the role of the connecting part is IPSec gateway to gateway, when in the IKE policy the Direction type is Initiator and the Exchange mode is Aggressive. And you will need to receive all additional configuration parameters from WiTopia -the Encryption, Authentication Algorithm, PFS, SA lifetime and so on. But this means that WiTopia have to provide gateway to gateway VPN connection.
Regards,
Kremena