Checking Empty Date-InputFields (reportContextAttributeMessage)

Hi there,

If i have an InputField mapped to an attribute of type date and if check this InputField (so in fact: if I check the attribute) for being a correct (whatever that means) date, then I have one serious problem:

If the user has not typed in something, the value is null. I can check this, but when I try to report a message like "Please type in something" bound to this context attribute, the server throws an exception that for reporting messages for a context attribute this attribute must not be null.

Any workaround?!

Thanks in advance

Detlev