1) the outgoing interface's IP address used by the device agent on the respective ASG is contained within the local network boundary defined for the IPSec VPN
2) ACC's IP address as specified for the device agent connection is contained within the remote network boundary for the IPSec VPN
If 1) and 2) are met, meaning both addresses fit to the IPSec SA, usage of your existing VPN should be possible. Note that ACC has no IPSec gateway functionality whatsoever, you will need to have an additional ASG as tunnel endpoint.
If the device agent IP address is outside the local network definition for your IPSec VPN you need to define an additional IPSec VPN connection where your local network is or contains the device agent IP address.
