Modifying the selection screen

Hi All

Can anybody please give me an idea about how to handle the radiobuttons in selection-screen .Based on the radiobutton selected I need the different input value fields.

This I have done with the addition USER-COMMAND

while defining the radiobutton field and by using MODIF ID extension and writing the code in AT SELECTION-SCREEN OUTPUT event. It is working fine in 4.7 version but not in 4.5B version.

Can anybody please suggest me on this

Thanks in advance

Satya