freight allocation to inventory

hi

We run dynamics NAV 2009 SP1 ver 6

My query is about allocation of freight and other expenses incurred in bringing inventory to the warehouse.

(1) A typical purchase would have 4-5 different items.

(2) We raise a purchase invoice on the supplier for the inventory and book a separate freight expense on the shipping company

We want the freight cost to allocated item wise , so that we can see it in the unit cost of the various inventories.

Eg ;

Purchase Inoivce

Item a - $400
Item b - $ 600

Total Freight - $10

New inventory cost

Item a - $104
Item b - $ 106

How can this be done automatically by the system ?

If you are using charge items for Freight calculation then use suggest Item Charge Assignment function in Item Charge Assignement