Hi Harut:
     Would you be able to find the derby_core_plugin_10.6.2.999685.zip and derby_ui_doc_plugin_1.1.2.zip from this web page http://db.apache.org/derby/releases/release-
Hope this help,

From: Harut Margaryan <hartuk18@gmail.com>
To: derby-user@db.apache.org
Sent: Sun, November 7, 2010 11:52:53 AM
Subject: Feedback releases/release-

Helllo please I need some help from your administartion. I could'nt find derby_core_plugin and derby_ui_plugin for installing to Eclipse IDE. 
What I must do to resolve that problem?

thanks for taking into consideration.