Binding a Grails date from params in a controller

Why is it so hard to extract the date from the view via the params in a grails controller?

I don't want to extract the date by hand like this:

instance.dateX = parseDate(params["dateX_value"])//parseDate is from my helper class

I just want to use instance.properties = params.

In the model the type is java.util.Date and in the params is all the information: [dateX_month: 'value', dateX_day: 'value', ...]

I searched on the net and found nothing on this. I hoped that Grails 1.3.0 could help but still the same thing.

I can't and will not believe that extracting the date by hand is necessary!