FireEye Add-on for Splunk Enterprise: How do I connect to a heavy fowarder?

I was able to simply install the FireEye TA on my all-in-one DevOps Splunk; configure the HX appliance to send JSON via HTTP POST to Splunk's API on 8089... without a problem I got the alerts in the index and sourcetype as defined in the HX appliance notifications. But now I am having trouble trying to send it to a HF before the indexers... Any suggestions or how to(s) appreciated. Thank you