diff --git a/parabotv2/src/org/parabot/core/asm/adapters/AddCallbackAdapter.java b/parabotv2/src/org/parabot/core/asm/adapters/AddCallbackAdapter.java
index 91e0903..3952575 100644
--- a/parabotv2/src/org/parabot/core/asm/adapters/AddCallbackAdapter.java
+++ b/parabotv2/src/org/parabot/core/asm/adapters/AddCallbackAdapter.java
@@ -6,6 +6,8 @@ import org.objectweb.asm.Label;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
 import org.objectweb.asm.tree.InsnList;
+import org.objectweb.asm.tree.InsnNode;
+import org.objectweb.asm.tree.JumpInsnNode;
 import org.objectweb.asm.tree.LabelNode;
 import org.objectweb.asm.tree.MethodInsnNode;
 import org.objectweb.asm.tree.MethodNode;
@@ -26,15 +28,17 @@ public class AddCallbackAdapter implements Injectable, Opcodes {
 	private String invokeMethod;
 	private String desc;
 	private int[] args;
+	private boolean conditional;
 
 	public AddCallbackAdapter(final MethodNode method,
 			final String invokeClass, final String invokeMethod,
-			final String desc, final int[] args) {
+			final String desc, final int[] args, final boolean conditional) {
 		this.method = method;
 		this.invokeClass = invokeClass;
 		this.invokeMethod = invokeMethod;
 		this.desc = desc;
 		this.args = args;
+		this.conditional = conditional;
 	}
 
 	@Override
@@ -60,6 +64,12 @@ public class AddCallbackAdapter implements Injectable, Opcodes {
 		inject.add(new MethodInsnNode(INVOKESTATIC,
 				this.invokeClass, this.invokeMethod,
 				this.desc));
+		if(this.conditional) {
+			LabelNode ln = new LabelNode(new Label()); 
+            inject.add(new JumpInsnNode(IFEQ, ln)); 
+            inject.add(new InsnNode(RETURN)); 
+            inject.add(ln);
+		}
 		this.method.instructions.insert(inject);
 	}
 
diff --git a/parabotv2/src/org/parabot/core/asm/wrappers/Callback.java b/parabotv2/src/org/parabot/core/asm/wrappers/Callback.java
index f277a2f..17602ee 100644
--- a/parabotv2/src/org/parabot/core/asm/wrappers/Callback.java
+++ b/parabotv2/src/org/parabot/core/asm/wrappers/Callback.java
@@ -18,14 +18,16 @@ public class Callback implements Injectable {
 	private String invokeMethod;
 	private String desc;
 	private int[] args;
-
+	private boolean conditional;
+	
 	public Callback(final String className, final String methodName,
 			final String methodDesc, final String callbackClass,
-			final String callbackMethod, final String callbackDesc, String args) {
+			final String callbackMethod, final String callbackDesc, String args, final boolean conditional) {
 		this.method = ASMUtils.getMethod(className, methodName, methodDesc);
 		this.invokeClass = callbackClass;
 		this.invokeMethod = callbackMethod;
 		this.desc = callbackDesc;
+		this.conditional = conditional;
 		if (args.contains(",")) {
 			final String[] strArgs = args.split(",");
 			this.args = new int[strArgs.length];
@@ -44,7 +46,7 @@ public class Callback implements Injectable {
 
 	public AddCallbackAdapter getAdapter() {
 		return new AddCallbackAdapter(this.method, this.invokeClass,
-				this.invokeMethod, this.desc, this.args);
+				this.invokeMethod, this.desc, this.args, this.conditional);
 	}
 
 }
diff --git a/parabotv2/src/org/parabot/core/parsers/hooks/JSONHookParser.java b/parabotv2/src/org/parabot/core/parsers/hooks/JSONHookParser.java
index eea34eb..8a0fbb0 100644
--- a/parabotv2/src/org/parabot/core/parsers/hooks/JSONHookParser.java
+++ b/parabotv2/src/org/parabot/core/parsers/hooks/JSONHookParser.java
@@ -217,7 +217,7 @@ public class JSONHookParser extends HookParser {
 
 				String clazz = o.containsKey("class") ? this.get(o, "class") : interfaces.get(this.get(o, "accessor"));
 
-				c[j] = new Callback(clazz, this.get(o, "method"), this.get(o, "callclass"), this.get(o, "callmethod"), this.get(o, "calldesc"), this.get(o, "callargs"), this.get(o, "desc"));
+				c[j] = new Callback(clazz, this.get(o, "method"), this.get(o, "callclass"), this.get(o, "callmethod"), this.get(o, "calldesc"), this.get(o, "callargs"), this.get(o, "desc"), false);
 			}
 			return c;
 		}
diff --git a/parabotv2/src/org/parabot/core/parsers/hooks/XMLHookParser.java b/parabotv2/src/org/parabot/core/parsers/hooks/XMLHookParser.java
index 8f44a3b..d237216 100644
--- a/parabotv2/src/org/parabot/core/parsers/hooks/XMLHookParser.java
+++ b/parabotv2/src/org/parabot/core/parsers/hooks/XMLHookParser.java
@@ -445,9 +445,10 @@ public class XMLHookParser extends HookParser {
             final String callDesc = getValue("calldesc", addCallback);
             final String callArgs = getValue("callargs", addCallback);
             final String desc = getValue("desc", addCallback);
+            final boolean conditional = isSet("conditional", addCallback);
 
             final Callback callback = new Callback(className, methodName, desc,
-                    callClass, callMethod, callDesc, callArgs);
+                    callClass, callMethod, callDesc, callArgs, conditional);
             callbackList.add(callback);
         }
         return callbackList.toArray(new Callback[callbackList.size()]);