Calculating HTTPS Payload in Splunk

Let me explain in this way, I have a website that is serving in HTTPS format. The traffic is arriving encrypted so to say. for testing environment I configured a FTP server without SSL certificate and I could receive the "bytes-out" and "bytes-in" in splunk with no problem, however when I receive the data from my website which is in HTTPS format none of the "bytes-out" and "bytes-in" fields are not shown in splunk. I have configured a Virtual Server with HTTPS which is a passthrough for HTTPS traffic.