search module problem

[mauretto78]

Hi All,
website joomla 2.5 with vm 2.024.
I'm using the virtuemart search module to display product by SKU.
Sku is always by 6 number and it start with 0.
if i'm searching the whole SKU number like "042651" , working perfect, but, for example,  if i only write "04" the page results show product with the SKU starting with "04" (es."042651") and others that contain the value "04" (es. 089041)
I need the search module start searching by the first two or three value of the SKU and not the whole SKU.
Can't find a solution...
Anyone had the same and know a solution?
Thanks a lot