I don't know how to code worth anything. I do happen to be a very frequent regular in an irc for a private server that's in development. Packets and how decoding them and such, are often used when making a private server from scratch. Just by watching/participating in that irc, I've learned quite a bit. If I had an code skill at all, I could also probably even do a basic private server myself.
(Note: It's a private server for a different game, not sro.)
Edit: as for your last question. I don't honestly know for sure, but I can try and find out.
Edit 2:
Mick = one of the developers
SSchi = me
[21:30] <Mick> >_>
[21:30] <SSchi> like i was saying lol
[21:30] <SSchi> a question about packets...
[21:30] <Mick> lol
[21:30] <Mick> whats that
[21:30] <SSchi> I have a question for you Joey: Is it possible to do as someone else said above, to disguise the GM's packets as a monster packet? That sounds like a good idea.
[21:30] <SSchi> Joey = me
[21:31] <Mick> lol...
[21:31] <Mick> that makes no sense at all
[21:31] <SSchi> i'll link you to the topic <_<
[21:31] <Mick> the packet type is defined by the op code in the header
[21:32] <Mick> so its either a packet to do with monsters, gm commands, or whatever
[21:32] <Mick> you can change the payload
[21:32] <Mick> but that will just make it an invalid packet
[21:32] <SSchi> well
[21:32] <Mick> you can change the payload to contain assembly
[21:32] <Mick> for a buffer overflow attack
[21:32] <SSchi>
http://www.silkroadforums.com/viewtopic.php?t=20254
[21:32] <Mick> but that has nothing to do with gm packets
[21:33] <SSchi> basically, srobot seems to work on packets
[21:33] <SSchi> and it can detect gm's, so i'm guessing gm's send special packets
[21:34] <Mick> oh, your wondering how a bot can detect a gm?
[21:35] <SSchi> hmm...
[21:35] <Mick> gm's probably have a field in thier spawn packt
[21:35] <Mick> or
[21:35] <Mick> the bots have a library of gm names
[21:35] <Mick> easy enough to detect a gm or anything
[21:35] <Mick> nothing to do with hiding packets in other packets
[21:35] <SSchi> just how the gm's might be able to hide their identity so it doesn't make the bot go "hey, there's a gm around, time to disconnect the client!"
[21:36] <Mick> oh, gms need to hide
[21:36] <Mick> then just make normal chars and log in like that
[21:36] <Mick> simple
[21:36] <Mick> or update their protocol to make gm spawn packets the same as normal player spawn packets
[21:36] <Mick> i.e. remove the gm flag, if such a flag exists
[21:37] <Mick> will require a client update too