Enter the Invoices as Vendor Invoices (this debits the expense account of the "freight" and "customs clearance" products)

When you create the Landed Costs, just enter the same product(s) from the Invoice(s) and the price for both that is applicable to what was received (this credits the expense from the invoice and debits the inventory account).  Note this approach allows you to allocate a single Vendor Invoice to multiple shipments as is compatible with the way you are billed by your freight and customs vendors. 

The price of your products will now be valued at the purchase price + freight + customs clearance.

Example:

Purchase 10 bottles of wine at $15 each - Inventory initially valued at $150 when received.

Enter Invoices and create Landed Costs of $15 for freight and $45 for customs clearance.  On validation of the Landed Cost, the Inventory will now be valued at $210.  

Just make sure Landed Costs is checked on the Invoicing tab of each Product for which you plan to use.