How to hide the selection screen fields of LDB in the report?

Hi All,

I am using LDB PSJ in my Report and this LDB has the selection screen. I want to hide certain fields(Proj-Pspid,Prps_r-posid,aufk-aufnr and act01-vornr) of this LDB's selection screen,how to go about it?

I have read the earlier posts and also tried using AT SELECTION-SCREEN OUTPUT waala funda but to no avail.

Where do we have to write this AT SELECTION-SCREEN OUTPUT -

in report or the Selections of the LDB???

One more thing----Can I change SAP standard LDB? If yes,how?