Hi Juan,
Which specification do you use?
There's the outdated
Gnutella - A Protocol for a Revolution and newer specs on
GDF - LimeWire (currently hosted by LimeWire).
If you need help in the implementation, please don't hesitate to ask here or in the gdf mailinglist!
(though as you already saw you can't be sure you'll get answers there... I'm reading it, as do many others, but as usual in free software projects, the time budget is always low)