How to allow end vpn user to access via Site to site zone traffic?

What I have understood from your post, the question is: You want to access something behind the Site to Site tunnel and you want the SSL vpn users to access it. If my understanding is right, kindly find the answers below. 

You will need to create a policy in Branch A where the SSL VPN users connect. 

Policy:  Incoming interface: SSL TUNNEL   & Outgoing Interface: Site to Site Tunnel

Also, you need to add the SSL VPN subnet in the Site to Site VPN phase 2 on both the end.  

Note: If you have Split Tunnel enabled, kindly add the destination subnet in the Routing Address in SSL VPN settings. 

If my answers are wrong, correct me! 

Thanks.