Hi,
 
I recommend reading this response as it will give you some context:
https://devcentral.f5.com/s/feed/0D51T00006i7cquSAA
 
For what you describe, you're currently doing SSL tunneling, which means the F5 is NOT decrypting the traffic but sending it as it is to the backend.
 
To decrypt the traffic on the F5, you need to create a ClientSSL profile and attach it to the correspondent virtual server. Then you have to decide whether you're going to re-encrypt the traffic or not before sending to the backend. If so, you'll also need a ServerSSL profile on the same virtual server, if you plan to send the traffic unencrypted from the F5 to the backend, then you only need the ClientSSL profile.
 
You'll find the information you need here:
 
https://support.f5.com/csp/article/K14783
 
https://support.f5.com/csp/article/K14806