I'm pretty sure it still doesn't work and probably won't ever work. The reason for the change surely as to do with the huge security flaw it would create.
Having this option would let any mod upload what they want to an external server. This include username, password, credit-card number, personal informations, etc.
This is only a guess, not the official reason since I have no idea.
Since S2Games lack standards, there is a way around this.
It's a bit tricky but here's a hint for you:
(now i'm just guessing since you'er reading this post, you're some what a geek.. and you'll probably be familar with stuff like DNS servers, routing/tunnling traffic)
install: DNS server
point: masterserver.hon.s2games.com & heroesofnewerth.com -> 127.0.0.1
point: relay all other querys to a real master DNS server (not your own).
Now esentially what you got is a small-time hack that lets you forward w/e traffic you want or not want to the real HoN server.
Secondly, it lets you respond with w/e you want instead of the actual HoN master server.
This way you can interrupt your newly created .honmod <form> post and reply with the proper response or you can use it to communicate with a 3:d party software of your choice.
Now i'm trying to figure out a way around this to make as easy as it was a few patches ago since it's obviously still insecure.