I personally prefer to flag the current year to date dates for all years in my application, so I would only accumulate for those values. But I guess this is more a design/display issue than an accumulation one, so you may change your bar background color to white or whatever your background color is if date is longer than today, on the [+] icon expanded in the Expressions tab.
I'm doing a full accumulation on the YTD figures, so the set analysis approach doesn't seem to work.
I've tried to make the background criterias, but it doesn't seem to work either (I'm a QlikView rookie, so poerhaps thats the reason :-). I've used the following formulas for the background color criteria: