How do I create a heat flux from a csv file in Optistruct?

Hello, I started using hypermesh recently for my thesis and I want to perform an structural optimization on a wing. For that I want to include the heat flux that enters the wing, which is calculated externally and stored in a csv file. In the documentation is stated that the flux panel from analysis can import csv files, but I am not given the option:  

I do not know what is the problem, or if I have to define something previously. I have already imported a pressure profile in another csv file and it work fine so I have no clue.
I attach the page of the documentation I read: https://help.altair.com/hwdesktop/hm/topics/panels/help086.htm
Alvaro