Categories and Subcategories

We have made Categories and Subcategories but the problem that it shows the subcategories as Categories and not the child of the main category. Is there any Hack to make it appear as a sub category?
Example:

Main category
– Sub category 1
– Sub category 2
– X category 1
– X category 2

We have installed sub category on the wp admin but shows the same
http://www.garticles.net

Thanks