Hello John I,
Welcome to the OptoForums!
Could you give us a bigger-picture view of what you're trying to do here? Usually SNMP is not the easiest way to do it, perhaps there's another way. FYI, be sure to check out this [SNMP 101 post, and perhaps also [URL="http://www.opto22.com/community/showthread.php?t=170"]this SNMP discussion](http://www.opto22.com/community/showthread.php?t=907) which includes some sample OptoScript code/charts. Note that the second discussion I mentioned there includes 2 pages and the 1st reply on the last page is from someone claiming to have done something similar to what you're trying to do there. You might post a reply to that thread and ask for details.
However, since you mentioned Wireshark and rolling your own UDP packet (fun stuff!), I'd also like to address your comment about typing an ASCII 0x00. You can still build a string in PAC Control with whatever binary values you want in it (I do it all the time, often to re-create packets I've sniffed in Wireshark). In OptoScript, it'd just look something like this:
MyString = "hello" + chr(0);
Or in an Action Block, you can use the String command "Append Character to String" where the character you're appending would be a zero. (The help on that command also gives the OptoScript equivalent.)
BTW, although we don't quite yet "officially" support UDP in comm handles, it's just a matter of documenting it and lots of folks are using it all the time. Check out this post on udp for details.
Hope that helps. I hope you'll report back on how do did (or share code! we love shared code!)