Commerce rules - refereing a product property (good on)

Hi all,

I am interested to create a rule able to limit the quantity of a certain product MyProduct based in a property field of MyProduct:max_quantity.

After reading http://www.drupalcommerce.org/faq/rules-field-data-selection, I defined a "Entity has field" max_quantity. But If I want to create another condition such as "commerce-line-item:quantity" is greater than MyProduct:max_quantity I can't because I can't select "MyProduct:max_quantity".

Any one have some idea?

Once I'll be able to establish this condition, I'd like to crate an action with:
Set value "commerce-line-item:quantity" to "MyProduct:max_quantity".

How can I define this rule?, is it possible?

Thanks,
Xavi