I have two tables that have many to many association between them. The tables are Product and Attribute. Many to many association is resolved using an associative table Product_Attribute. The table structure is as follows

Product
--------
Product_ID (PK)
Name

Attribute
----------
Attribute_ID (PK)
Name

Product_Attribute
--------------------
Product_Attribute_ID (PK)
Product_ID (FK)
Attribute_ID (FK)
Date
Value

The associative table uses a surrogate key but also introduces a new columns like Date and Value. If these extra columns would not have been present than I could have map this relationship using idbag. If the associative table would not have introduced the surrogate key than I could have mapp the relationship using composite-element. Is there any way i can use idbag with composite element (or any other solution) to map the above mentioned relationships.