Trouble with Autobench and setting httperf_add-header

Question

I want to load test my application and need a Cookie for it. I've looked all of the other questions and have tried this:

In autobench.conf

httperf_add-header = "Cookie: cookie_name=cookie_string\n"

Still not working. I believed is ignored.

But, when I run httperf like:

httperf --add-header="Cookie: cookie_name=cookie_string\n" --server=server --port=port--uri=/uri

It works perfect.

So, how do i make it work for Autobench?

Thanks in advance.