how to add further stock items?

stufflearn (Practioner) (102 Points)

09 February 2010  
Hi, I have created a stock item say "X" and put opening balance of "1000" qty. on 1st January. Now we have got the same stock again about 500 qty and we want to add this 500 to that 1000 so that it can show "1500" quantity for "X" item. I wonder how to do it? If I open "X" item now it shows just 1000 qty as an opening balance along with the date 1st January. Any help would he highly appreciable. I'm using 7.2 version.