How to set charset for wp_remote_post request?

After trying several times to set the proper charset, I wasn’t successful. Then I searched for an workaround and found one that worked with my problem.

In addition to set the charset like I mentioned above, what I did is to convert all strings on my POST body with this php snippet:

$message = @iconv("UTF-8","Windows-1252//IGNORE",$message);

This converts all of your characters into compatible Windows-1252 strings. For me, it worked, and all special characters are properly recognizable on the ISS server.