Hi guys I have tried to add field to_invoice and product_id inside of the Project->Task -> Work Summary

But how ever I try he is telling me that xml is wrong.. I found one modul which is adding some button, and he is working and I tried to edit it just to add these fields or some regular text field and when I try it says again that xml is wrong..

Anyone done that? Or have a clue how to do that?

this is my code: http://pastebin.com/yYLEYZBg