code: public String getCustomBundleProperty(String bundleName, String key, String defaultValue) {
  		return props.getProperty(prefix + PropertiesBundleConstant.BUNDLE_FACTORY_CUSTOM_PROPERTY + bundleName + key,
  				defaultValue);
  	}
docs: Returns the value of the custom bundle property, or the default value if
  no value is defined
  
  @param bundleName
  the bundle name
  @param key
  the key of the property
  @param defaultValue
  the default value
  @return the value of the custom bundle property, or the default value if
  no value is defined