Proxied SaaS site through APM

Hi All, Running 11.2.1 APM to provide remote access SSL VPN for IOS devices to internal sites. My company has started to use a SaaS ticketing system which is access via our Bluecoat Proxy solution. The Bluecoats are setup as explicit proxies using a different F5 to load balance the traffic.

I have been asked to provide access to the SaaS system via the APM SSL VPN and struggling how to do this as we normally just allow access to internal sites by routing directly through a firewall. Trying to proxy just one site is something I am having difficulties with.

Traffic flow would look like this:

IOS Device -> Internet -> External Firewall -> APM F5 -> Internal Firewall - > Proxy Firewall -> Proxy F5 -> External Proxy Firewall -> Internet -> SaaS

Any help or ideas would be appreciated.