"Multiple interface support with redundancy" or ISP redundancy is not supported for Endpoint Security VPN remote access clients.
Only static Link Selection is supported. This means that if ('Gateway Properties > VPN > Link Selection > "Use a probing method"') is selected, then the setting that will actually apply is (Gateway Properties > VPN > Link Selection > "Always use this IP address" > Main address').
When ISP redundancy is enabled and "Apply settings to VPN traffic" is selected this is also classified as a Probing Method of Link Selection and it will not be applied to Endpoint Security VPN clients.
Related Solution: sk56580 - SecureClient Feature Support in Endpoint Security VPN R75/E75.x.