Format Month in BIRT Report

Dear Friends, our scorecard period format is 2013/12 and on BIRT i need to display 'December' instead of the default format, can anyone help me to format this on bIRT. Actuate helped me to get output as Dec 2012, but i need to drop the year and only show Dec. this was the code they sent. when you preview it shows as 2012-12-01
and in birt if i show month it still shows as Dec 2012.

sDate = ""

sDate = row["PeriodName"] + "/01"

new Date(sDate)