Virtuemart 3 multi variation doesn't work

[OrazioGlam]

Hi guys,
I have a big problem with Multi Variation: in the backend I have correctly inserted all values of my variations, but in product details the <select> of variation is empty!
I've tried with different template (Beez2, Beez5 and Atomic) so I think is not a Javascript conflict. Finally I have analyzed the code HTML of the product detail page, and the tag <select> is totally empty! Anyone have an idea how to solve?

My configuration:
Localhost on Windows 10
php version 5.6.3
MySql 5.5.45
Apache Lounge 2.4.10
Joomla 3.4.5
Virtuemart 3.0.12
Template: GCK Store from Shape5.com (but there is the same problem with all templates)

Thank in advance for your help!