Drupal Commerce.Configure multiple VAT

One week ago i began a new project in Drupal ,a medical online shop. My first choice was Ubercart solution, this is an stable e-commerce solution.
I was testing with Ubercart at first but i had a problem with multiple VAT configuration.
I was looking for a solution and i found one in http://carlos.rinconsanchez.com/multi-iva-con-drupal-commerce
I didn't get on to solve my problem with this article, but it gave me a good track.

This is my solution:

1) Create taxes. I have created two VAT taxes: 10% and 21%.
2) Add a new property to commerce product entity: Add a new VAT text selection control field.
iva 10|10
iva21|21
3)Configure rules for taxes:
configure components
add one condition for each tax:
Entity exists by property
Parameter: Entity Type: Commerce Product, Property: Iva, Value: 10

Entity exists by property
Parameter: Entity Type: Commerce Product, Property: Iva, Value: 21