IPSEC - Road Warrior to Main-Office to Branch Office

[Besth]

Hello,

my setup looks like this:
My Main-Office A is 10.99.x.x/16 and is connected over ipsec-vpn ikev2 with the branch-office B 10.199.20.x/24.
On both ends are pfsense-Firewalls.
This works fine. i can communicate in both directions.

I use the "VPN/IPsec/Mobile clients" feature for my roadwarrior C users to Main-Office A. They can connect to my Main-Office A pfsensebox (10.99.1.1/16) with their clients like Windows-PC or Android-Smartphone. They get an ip like: 172.20.x.x/16
They can now use the services in my main-office A and reach all servers.
But they can not reach my branch office B.

What will i need to configure to route traffic from road-warrior C to branch-office B over main-office A?
is it even possible?

I thought when i change the road-warrior C IP to 10.99.150.x/24 its working, but it doesn't. Now i can't reach the services in main-office A. The router 10.99.1.1 is pingable but not the servers.

[Besth]

someone got a hint on this?