APM logs are going to be sent in the same syslog payload - you just need to ensure that you have the APM logging set at the appropriate level in the BigIP settings.
I would also like to know how to send APM logs to a Splunk instance. LTM logs are being sent ok but wondering how to specifically send the APM logs. We are using LTM/APM 11.3.
Looking for some assistance on this as well. I have been able to locate good information on logging required for the Splunk F5 Network app but not the F5 Access app.