It is unclear what the networks look like. It is unclear if the client subnet you are asking about is completely separate from your gateway connections, such as:
Code:
[Your company gateway at IP address a.a.a.a] - { the Internet}
[Your client gateway at IP address b.b.b.b] - {the Internet}
[The 200.185.190/24 subnet somewhere in Brazil] - {the Internet}
If that is accurate, then you would need a gateway device on that client subnet.
But, perhaps the client subnet includes the gateway?
Code:
[Your company gateway at IP address a.a.a.a] - { the Internet}
[Your client gateway at 200.186.190.x] - {the Internet}
If so, you need only ensure the subnet is included in the ipsec.conf(5) configuration. An example of two subnets tunnelled between two gateways was used in Symantec's article
Zero to IPSec in 4 Minutes.