OpenVPN as client to a Fortigate firewall set for SSL vpn

Is there anyone here that has successfully establish a connection from a router running OpenWRT with openvpn package on it acting as a tcp client to a Fortigate firewall.
The Fortigate fw it's configured for SSL VPN and works with various clients (Windows , Linux, Macs) using the fortinet client software. Each user it's using a username and password plus a certificate for extended authentication.
The plan is to configure a OpenWRT router with those credentials and establish a vpn connection to the Fortigate firewall.
I did check what google search returned by I haven't got too far. Any help is greatly appreciated.