Problem Importing combinations

[ThunderPaul]

Hi,
I have a problem with import CSV file with combinations.

Il mio file è strutturato in questo modo:

id_product; reference; Attribute:nameAttribute:PositionAttribute; Value:PositionValue; Quantity
Since I need to import apparel products for each product sizes available with the appropriate quantity, the sample lines are as follows:

 

8; ref-xxx; Taglia:select:4; XS:21; 3;
8; ref-xxx: Taglia:select:4: S:22; 5;

8; ref-xxx; Taglia:select:4; M:23; 2;

When I import the csv file is only saved the ultimate combination for each individual product and not the previous ones. 

Do you know how to import the file correctly combinations?

Thanks