Purchasing inventory items through purchase invoices

When creating purchase invoice, I have item column where the inventory items does not show.

How to use this column to add the items in purchase invoice, so that it can be posted directly to the inventory on hand.

You should disable Item column by going to Settings tab, then Customize button and uncheck Purchase Invoice Items.

To purchase inventory item, use account Inventory on hand, then select inventory item.

Thanks for your support Lubos, One More Question here for you:
I am creating a purchase invoice and providing the desired details in required field. i.e. The unit price, and the Tax Scheme. After Creating the purchase invoice, all the calculations are perfect. While i am paying the suppliers by specnd money button, the purchase invoice gets paid in full.
After All that, when I am looking on summary page it shows the Tax Amount under Other Liabilities and sub Category of Tax Payable.
If I have already paid the tax to supplier then why i am having the liability to pay the tax again?
Please help me, whether i am doing something wrong ?

Apart from the Above, Why The Indian currency symbol is not appearing even after typing in the prefix currency box.