product minim 2 units purchase

Hi, I need buy a item that minim quantity are 2. I like that in most popular articles (home page) customers can buy 2 units of this item directly.
Now when customer select item, show message that minimun are 2 quantity and go to list categories.
Is possible in home page show quantity and default quantity 2 before press + button?
What other solution can i do?

My example:
http://botiga.lacalendula.net/

You should ask about it on VirtueMart support forum because this issue depends of this extension and VM as a 3rd party extension is beyond our support.