How to support JSF Core 'f:loadBundle' resource messages?

Hello,

i have :
  <f:loadBundle basename="de.eskalon.nobiskrug.frontend.messages" var="msg" />
  while f is (xmlns:f="http://java.sun.com/jsf/core")

now <h:outputText value="#{msg['foo']}" /> has 2 problems:

* bean type is unknown but property navigation to property file works
* when i declare msg type as java.util.Map , the eban type is known but property file navigation does not work any more

what could i do to not have one of those drawbacks?

Chers
JB