in line grid with currency

Hi,

I am currently working on developing inline grid functionality for invoice line items instead of second page grid. customer would like to have same inline grid functionality like we have at invoice line item- VAT defining screens. i have developed screens with required fields. But however whenever I add a second currency field(prepaid amount or freight rate value), I receive an extra rows with only ">" character for every line item. If I add any other text fields, number or drop down fields, all they work.

Customer would like to update the fright charge of all the invoice line items one by one in a grid instead of navigating to edit page and then saving and then re-opening a new page. Also they need a single screen with all other fields(very less) rather than multiple tabs. Also in the XML DOM, I see the values being populated.