How FI values are passed in Hover

Hi ,

I need your help in a following case where I am trying to create a new hover form. For example let us consider this application P41700 which is hover application in this we can able to see item number and MCU as form data structure and when we click on that small orange button on Item Number it will pop the form of P41700 and the item number is passed in FI values and this is used to fetch other values in the dialog is initialized event.

Now my query is how this Item Number value is passed as FI value to P41700, Because in my custom application i used a URCD field as FI value and did the coding and made configurations in P958973 and P958974 and I could see a orange button (hover enabled) in the URCD field of the application for which the hover is configured. But when it is clicked I could not see the data related to the value present in the grid cell . Reason is the FI value for the URCD field is passed as blank.Do we need to do