Forgot the AddOn wrapper in the last commit.

src/com/kwanzoo/recurly/AddOn.java

@@ -0,0 +1,16 @@
+package com.kwanzoo.recurly;
+
+import javax.xml.bind.annotation.XmlElement;
+import javax.xml.bind.annotation.XmlRootElement;
+
+@XmlRootElement(name="add_on")
+public class AddOn{
+	@XmlElement(name="add_on_code") 
+	public String 	addOnCode;
+
+	@XmlElement(name="unit_amount_in_cents") 
+	public Integer 	unitAmountInCents;
+
+	@XmlElement(name="quantity") 
+	public Integer	quantity;
+}