1º step: download Java Bytecode Editor http://set.ee/jbe/

2º step: open you plugin with winrar! and open "Plugin.yml"

3º step: Find Main Class of plugin
http://i.imgur.com/yMuX9vj.png

4º step: find for the main class in your plugin example "com.shynixn.blockball.business.bukkit.BlockBallPlugin"
go to folders
http://i.imgur.com/H74GVgr.png

5º step: Copy the class found and open with JavaBytecodeEditor like this:
http://i.imgur.com/nOyq38c.png
http://i.imgur.com/mYQKSIh.png

6º step: Open methods/loadconfig and click on [0]Code
http://i.imgur.com/FLWiXjS.png

7º Step: go to Code editor and find "idc"
http://i.imgur.com/FAL5tF9.png

8º step: change the url change anything from this url example:
http://www.spigotmc.org/api/resource.php?user_id=19996&resource_id=644&nonce=-1993687303
to
http://www.spigotmc.org/api/resource.php?user_id=xxx


save and import to winrar archive