[rules-users] MVEL and Maps

Hello, I'm feeding my working memory with Maps (unfortunately, this is a requirement and I can't use beans). To access the values in this maps I use the following MVEL expression : Map ( this["airportCode"] == "GIG" , this["numberOfPassengers"] > "1" , this["class"] memberOf ("BUSINESS", "FIRST") ) And it works fine, except for dates where I get a ClassCastException, even tough I'm using the right pattern: Map ( this["departureDate"] > "07-Nov-2009" ) --- fails Is there anything I need to do to make the dynamic cast of dates work, in this particular case? -- Morever, I get NPEs if there's no value for a given key. For example, the expression Map ( this ["name"] == 'Leonardo' ) would fail if there's no entry with "name" as the key. Any help is welcome! Thanks in advance, Leo.