diff -r c7881f2e2e05 groovy.grailsproject/src/org/netbeans/modules/groovy/grailsproject/plugins/GrailsPluginsManager.java
--- a/groovy.grailsproject/src/org/netbeans/modules/groovy/grailsproject/plugins/GrailsPluginsManager.java	Fri Aug 01 14:50:09 2008 +0200
+++ b/groovy.grailsproject/src/org/netbeans/modules/groovy/grailsproject/plugins/GrailsPluginsManager.java	Mon Aug 04 11:38:12 2008 +0200
@@ -45,7 +45,6 @@
 import java.io.File;
 import java.io.InputStream;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -55,6 +54,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
+import java.util.prefs.Preferences;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.zip.ZipEntry;
@@ -77,6 +77,7 @@
 import org.openide.util.Exceptions;
 import org.openide.util.HelpCtx;
 import org.openide.util.NbBundle;
+import org.openide.util.NbPreferences;
 import org.openide.xml.XMLUtil;
 import org.w3c.dom.Document;
 import org.w3c.dom.Node;
@@ -88,6 +89,16 @@
  */
 public class GrailsPluginsManager {
 
+    private static final String HTTP_PROXY_HOST = "http.proxyHost"; //NOI18N
+    private static final String HTTP_PROXY_PORT = "http.proxyPort"; //NOI18N
+    private static final String HTTP_PROXY_USER = "http.proxyUser"; //NOI18N
+    private static final String HTTP_PROXY_PASSWORD = "http.proxyPassword"; //NOI18N
+    private static final String NB_USE_PROXY_AUTHENTICATION = "useProxyAuthentication"; // NOI18N
+    private static final String NB_HTTP_PROXY_HOST = "proxyHttpHost"; //NOI18N
+    private static final String NB_HTTP_PROXY_PORT = "proxyHttpPort"; //NOI18N
+    private static final String NB_PROXY_USERNAME = "proxyAuthenticationUsername"; // NOI18N
+    private static final String NB_PROXY_PASSWORD = "proxyAuthenticationPassword"; // NOI18N
+    
     private final GrailsProject project;
 
     private GrailsPluginsManager(GrailsProject project) {
@@ -103,9 +114,10 @@
 
         final ProjectInformation inf = project.getLookup().lookup(ProjectInformation.class);
         final String displayName = inf.getDisplayName() + " (" + command + ")"; // NOI18N
-
+        
+        loadHttpProxyProperties();        
         final Callable<Process> callable = ExecutionSupport.getInstance().createSimpleCommand(
-                command, GrailsProjectConfig.forProject(project));
+                command, GrailsProjectConfig.forProject(project));        
 
         final PluginProcessor processor = new PluginProcessor();
         ExecutionDescriptor descriptor = new ExecutionDescriptor().frontWindow(true);
@@ -113,7 +125,7 @@
             public InputProcessor newInputProcessor() {
                 return InputProcessors.bridge(processor);
             }
-        });
+        });        
 
         ExecutionService service = ExecutionService.newService(callable, descriptor, displayName);
         try {
@@ -194,6 +206,7 @@
                 }
             });
 
+            loadHttpProxyProperties();
             Callable<Boolean> runner = getInstallPluginCallable(plugin, buttons[1], dlg);
 
             final Future<Boolean> result = executor.submit(runner);
@@ -224,7 +237,7 @@
                 String[] args = plugin.getPath() == null
                         ? new String[] {plugin.getName(), plugin.getVersion()}
                         : new String[] {plugin.getPath()};
-
+                
                 Callable<Process> callable = ExecutionSupport.getInstance().createSimpleCommand(
                         command, GrailsProjectConfig.forProject(project), args);
                 ExecutionDescriptor descriptor = new ExecutionDescriptor().frontWindow(true)
@@ -323,6 +336,28 @@
         }
         return plugin;
     }
+    
+    //WARN: This method overrides the default System proxy properties.
+    private void loadHttpProxyProperties() {
+        Preferences prefs = NbPreferences.root().node("org/netbeans/core"); // NOI18N
+        
+        final String host = prefs.get(NB_HTTP_PROXY_HOST, System.getProperty(HTTP_PROXY_HOST));                  
+        if (host == null) {
+            return;
+        }
+        System.setProperty(HTTP_PROXY_HOST, host);
+
+        final String port = prefs.get(NB_HTTP_PROXY_PORT, System.getProperty(HTTP_PROXY_PORT));        
+        if (port != null) {
+            System.setProperty(HTTP_PROXY_PORT, port);
+        }
+        
+        final boolean useAuth = prefs.getBoolean(NB_USE_PROXY_AUTHENTICATION, false);        
+        if (useAuth) {
+            System.setProperty(HTTP_PROXY_USER, prefs.get(NB_PROXY_USERNAME, ""));
+            System.setProperty(HTTP_PROXY_PASSWORD, prefs.get(NB_PROXY_PASSWORD, ""));                  
+        }        
+    }
 
     private GrailsPlugin getPluginFromInputStream(InputStream inputStream, String path) throws Exception {
         final Document doc = XMLUtil.parse(new InputSource(inputStream), false, false, null, null);
@@ -340,7 +375,7 @@
         }
         return new GrailsPlugin(name, version, description, path);
     }
-
+    
     private static class PluginProcessor implements LineProcessor {
 
         private final List<GrailsPlugin> plugins = Collections.synchronizedList(new ArrayList<GrailsPlugin>());