IP of a Outgoing Request from AWS EC2 behind ELB

I have a single EC2 with a EIP behind a ELB. All the incoming requests are hiting the ELB and reaching EC2 webserver, as expected. Now from my PHP application I do a Outgoing Curl request to another server (not in AWS) and check the request IP there, it is showing the ELB IP from Pool. I was expecting it to show the EIP of the EC2.

Is there something that I am missing, do I need any specific header in Curl request to see EIP in another server?

https://forums.aws.amazon.com/thread.jspa?threadID=125346 this thread someone mentioned following, and i was expecting same.

When you receive incoming traffic through the load balancer, the responses will go out the same way. However, traffic that is originating from your instance will not pass through the load balancer. Instead, it is sent directly from the public IP address of your instance out to the Internet. The ELB is not involved in that scenario

via Chebli Mohamed