Remote access VPN connecting to Site to Site VPN

Hello!

Apologies for the confusing topic.

I've sent up the following:

1) A Forticlient VPN (assigning 10.0.5.0/24 network) access to the Fortigate for remote access to the office network (10.0.0.0/24)

2) a Site to Site VPN connecting the Fortigate to a remote Cisco ASA for office access to a rackspace hosted environment (172.24.16.0/22)

Both work fine standalone. In the office environment, I'm able to access the Rackspace environment. Outside the office, the VPN allows me to access the office environment.

I'm lost however allowing the remote devices which connect thru the Forticlient IPSec VPN, to connect to the Rackspace hosted network.

any direction would be helpful..