The poller sends 0xF1, 0xFF to your server. You need to respond with, the following string
"Sphere Name=<servername>, Clients=<clientcount>, Chars=<mobile count>, Items=<Item count>, Mem=<mem usage>"
Make sure each property is seperated with a , (comma) and each value and property item group are seperated with a =. Also, the packet ID is 0x53, but that is the ASCII character S, so you responde with 0x53 and the reset should be the string "phere Name=<servername>, Clients=<clientcount>, Chars=<mobile count>, Items=<Item count>, Mem=<mem usage>".
Let me know if this doesnt make sense...