I solved the problem..

first i created a class cCrystalPreviewOut that import cCrystalPreview...

Class cCrystalPreviewOut is a ModalPanel
Import_Class_Protocol cCrystalPreview

Procedure End_Construct_Object
Set Modal_State to False

Forward Send End_Construct_Object
End_Procedure
End_Class

when i have to print a report inside a dg i do this..

Object oCrystalPDM018 is a cCrystalMCM
Procedure OnInitializeReport Handle hoReport
Set phcPreviewObject to (RefClass(cCrystalPreviewOut))
Forward Send OnInitializeReport hoReport
End_Procedure
End_Object

thanks