Adding XSQL Tags
All XSQL tags can be inserted by selecting them from the Component Palette, as described below. You can also insert XSQL tags by typing them in the file. Code Insight is available for XSQL tags.
http://download-east.oracle.com/otn_hosted_doc/jdeveloper/904preview/creating_html_clients/xsql_paddxsqltags.html