Multi-VPN Access for VPN Client issue

Hi all,

In my company we have 3 sites interconnected with site-to- site IPSec VPN tunnels. This interconnection works fine.
I deployed SSL VPN Client for employees to access Main site servers and applications.
But now I have a problem to communicate between main network and branch network through IPSec VPN. 

I followed this guide "360005933859--ATP-VPN-Multi-VPN-Access-for-VPN-Client" and many others without success.

I created policy Routes to route traffic between the VPN client and Branch office.

Main Office : USG310
Branch Office : USG200

Do you know if this configuration is possible between a USG310 and a USG200 ? Do I need to replace USG200 by another more recent ? 

Thanks for help