purchage order

By Default in Create purchase order form get “vendoraccount” from “vendTable”. I created one new Form "indent"in that vendaccount field is there. This field also get values from vend table, Now my problem is :-- Create purchase order form-- vendoraccount should have the value from "indent"form how can i do this… ANY ONE CAN HELP ME PLZ…

You can override the lookup method to achieve this.