It used to be possible to manually add the plugin portal in the IDE using the following URL http://plugins.netbeans.org/nbpluginportal/files/nbms/pluginportal-update-center.xml. However, the most recent version of this file contains unquoted 
ampersand (&) characters in two places in the plugin names and that breaks the XML parsing of the catalog file. Just look at the following attributes on 
lines 630 and 1058 of the file dated Dec 4: OpenIDE-Module-Display-Category="Web & Java EE".

<module codenamebase="org.netbeans.modules.web.spring.framework"  
distribution="http://plugins.netbeans.org/nbpluginportal/files/nbms/1196642071301_spring-support-plugin-1.1.nbm"  downloadsize="10839363"  
homepage="http://spring-netbeans.sourceforge.net"  license="808"  moduleauthor="Craig MacKay, Rohan Ranade"  needsrestart="false"  
releasedate="2007/12/02">
<manifest   OpenIDE-Module="org.netbeans.modules.web.spring.framework"  OpenIDE-Module-Display-Category="Web & Java EE"  OpenIDE-Module-
Implementation-Version="071202"  OpenIDE-Module-Java-Dependencies="Java > 1.5"  OpenIDE-Module-Long-Description="Provides support for the 
Spring Framework"  OpenIDE-Module-Module-Dependencies="org.jdesktop.layout/1 > 1.4, org.netbeans.api.java/1 > 1.13.1, 
org.netbeans.api.web.webmodule > 1.8, org.netbeans.libs.javacapi > 0.5.1.1, org.netbeans.modules.editor/3 > 1.35.1.4.2, 
org.netbeans.modules.editor.lib/1 > 1.20.1.4.2, org.netbeans.modules.j2ee.dd/1 > 1.10.0.2, org.netbeans.modules.java.project/1 > 1.12, 
org.netbeans.modules.java.source > 0.26.1.1.5, org.netbeans.modules.project.libraries/1 > 1.14, org.netbeans.modules.projectapi/1 > 1.13, 
org.netbeans.modules.projectuiapi/1 > 1.24.1.6, org.netbeans.modules.xml.catalog/2 > 1.12.0.4.4, org.netbeans.modules.xml.text/2 = 4, 
org.openide.awt > 6.11.1.1, org.openide.dialogs > 7.5, org.openide.filesystems > 7.2, org.openide.loaders > 6.7.1, org.openide.nodes > 7.2.1.1, 
org.openide.text > 6.16.1, org.openide.util > 7.9.0.1, org.openide.windows > 6.18.1"  OpenIDE-Module-Name="Spring Framework Support"  OpenIDE-
Module-Requires="org.openide.modules.ModuleFormat1"  OpenIDE-Module-Short-Description="Spring Framework Support"  OpenIDE-Module-
Specification-Version="1.1.0"/>
</module>

<module codenamebase="org.netbeans.modules.web.spring.framework"  
distribution="http://plugins.netbeans.org/nbpluginportal/files/nbms/1196642071301_spring-support-plugin-1.1.nbm"  downloadsize="10839363"  
homepage="http://spring-netbeans.sourceforge.net"  license="808"  moduleauthor="Craig MacKay, Rohan Ranade"  needsrestart="false"  
releasedate="2007/12/02">
<manifest   OpenIDE-Module="org.netbeans.modules.web.spring.framework"  OpenIDE-Module-Display-Category="Web & Java EE"  OpenIDE-Module-
Implementation-Version="071202"  OpenIDE-Module-Java-Dependencies="Java > 1.5"  OpenIDE-Module-Long-Description="Provides support for the 
Spring Framework"  OpenIDE-Module-Module-Dependencies="org.jdesktop.layout/1 > 1.4, org.netbeans.api.java/1 > 1.13.1, 
org.netbeans.api.web.webmodule > 1.8, org.netbeans.libs.javacapi > 0.5.1.1, org.netbeans.modules.editor/3 > 1.35.1.4.2, 
org.netbeans.modules.editor.lib/1 > 1.20.1.4.2, org.netbeans.modules.j2ee.dd/1 > 1.10.0.2, org.netbeans.modules.java.project/1 > 1.12, 
org.netbeans.modules.java.source > 0.26.1.1.5, org.netbeans.modules.project.libraries/1 > 1.14, org.netbeans.modules.projectapi/1 > 1.13, 
org.netbeans.modules.projectuiapi/1 > 1.24.1.6, org.netbeans.modules.xml.catalog/2 > 1.12.0.4.4, org.netbeans.modules.xml.text/2 = 4, 
org.openide.awt > 6.11.1.1, org.openide.dialogs > 7.5, org.openide.filesystems > 7.2, org.openide.loaders > 6.7.1, org.openide.nodes > 7.2.1.1, 
org.openide.text > 6.16.1, org.openide.util > 7.9.0.1, org.openide.windows > 6.18.1"  OpenIDE-Module-Name="Spring Framework Support"  OpenIDE-
Module-Requires="org.openide.modules.ModuleFormat1"  OpenIDE-Module-Short-Description="Spring Framework Support"  OpenIDE-Module-
Specification-Version="1.1.0"/>
</module>