Discount not assigned in subcategories

[delimpasis]

Joomla 2.5
VM 2.0.16

I searched for a while in the forum but I didn't find anything relevant.
I am inserting a discount for a category using:
DATax, -30% applied in Category 1, for all buyers, published and never ends.

I would expect that the rule should be applied to all subcategories' items but that is not happening. Instead if I add Item (currently in Subcategory 1.1) in Category 1, the discount appears normally. Is this how it should work?

[jenkinhill]

http://forum.virtuemart.net/index.php?topic=113237