Empty h:inputText field is being submitted with "" value - Is that right???

[Rafael Nami]

Well, good evening everyone (here in Brazil is 18:30).
I'm developing a web application using the Spring/Hibernate/JSF-MyFaces combo, and so far is being a silver bullet to me.
Well, I have several search forms in my webapp, but when I submit a empty inputText, the value passed to the backing bean is the "" value, and this is directly impacting in my backend, because I'm using Hibernate Criteria API for the search method. Is this "conversion" the right behavior? If it is, how can I convert this value to null??

Thanks in advance

Rafael Mauricio Nami