If you specify a POST type request, but you call send() or send("") or send(null) or send(false) -- basically, any type of empty request body, Flash has a bug where it will convert the request to a GET.

The problem with this is that pursuant to this bug on GETs and request headers dropping, if you have any request-headers defined for your POST, like "Content-type" or even "Authorization" (or used the username/password parameters to open(...) method), such request-headers will be summarily dropped when Flash converts it to a GET request.

The only known workaround is to send a non-empty body to get it to respect your POST method. You can send "." or " " or something else. Just make sure that you're sending something that won't screw up or confuse the target server.