Search using base functionality (AX2009)

Hi,

I'm trying to search with value that is different when input.

The table has the item of the YYYY/MM display format. But actually the data is YYYY/MM/01.

So when we search using base functionality, must input YYYY/MM/01.

But we want to search with just input YYYY/MM. 

First I thought using form task method. But I can't get search value and item.

How can I do this?

Thank you