From CyberWurx Customer Wiki

[edit] Enable Bukkit

To enable bukkit, log into your gamepanel account and view your minecraft server's server details. On the left hand side you will see Bukkit and a text box with either 1 or 0 inside.

Boolean value guide:

0 - Disabled
1 - Enabled
2 - Snapshot Build Enabled

Set this value to either 1 or 0 depending on if you want to enable or disable bukkit. Make sure you restart your server to apply the changes.

[edit] New!

You can optionally use the snapshot build of bukkit by setting bukkit to 2.