What version of VCS are you running? In X8.5 that just recently released, they've added the ability to add static routes via the web interface. See the VCS Release Note X8.5, pg 4 under "Other Changes".
It would be more handy if you could describe your current network setup which interfaces are used on the VCS, is the dual interface option present (is a requirement as you are trying to use two interfaces), which networks and hosts are where, ...
Also which software version you use can be helpful, as well as do a small drawing.
You listed two completely different commands, first the xcommand, which can only be used when logged in as admin via the CLI, the other which are linux-shell commands, which should not be used at all anyhow, and then how you used it (like setting a default route to the interface rather than to a gateway) looks not ok.
Please check the VCS admin guide, there you will find how to configure the basic and advanced network settings
*h 'xCommand RouteAdd' "Adds and configures a new IP route (also known as a static route)." Address(r): <S: 1, 39> "Specifies an IP address used in conjunction with the prefix length to determine the network to which this route applies." PrefixLength(r): <1..128> "Specifies the number of bits of the IP address which must match when determining the network to which this route applies. Default: 32" Gateway(r): <S: 1, 39> "Specifies the IP address of the gateway for this route." Interface: <Auto/LAN1/LAN2> "Specifies the LAN interface to use for this route. Auto: the VCS will select the most appropriate interface to use. Default: Auto"