Hi atassani,
The CA API Gateway application logs are stored by default in this directory: /opt/SecureSpan/Gateway/node/default/var/logs/ (in here you will find the ssg_0_0.log file which is the default file that the CA API Gateway writes to)
You can learn more around integration with Syslog (and external syslog servers like Splunk) on this page and the pages beneath it: https://wiki.ca.com/pages/viewpage.action?pageId=204713459
Using the instructions found on the pages for managing log and audit sinks, you can create a new one to suit your requirements on what needs to be logged and which file to log it to (or external syslog server if needed).
I hope the above points you in the right direction. If you have any further questions on setting up a Log Sink, please feel free to reply back to this thread.
Sincerely,
Dustin Dauncey
Support Engineer, Global Customer Success
Email: API-Support@ca.com
Phone: +1 800 225 5224
Outside of North America - ca.com/us/worldwide.aspx
CA API Management Community: ca.com/talkapi