Import Tax

Hello My English is not that good, everything work proper on FA the only problem i am getting is Import Tax,import duty when i add it to supplier invoice,it  doesn't increase  the inventory,taxes and duties that may not be recoverable from tax authorities have to increase the cost of the inventory or the product on the invoice,please help if there is ways to do it.

Eg

Supplier Invoice

desc        QTY     price    total

Lcd tv      10       100      1000

                             total   1000
          import tax  10%       100
                      total           1100

Now inventory cost of 1 LCD TV  = 110
when i try the cost remains the same it does not increase will appreciate your help

Khalifa Alnaamani