Change background dialog color

I have some SFX.bin code Fro TZip that creates a dialog:
How can I change the background dialog color from clbuttonface to
clwindow.  The dialog is in a res file and has menifest in the res as well.

I am used to dealing with vcl.

Thanks,

Bill

function Main(Dialog: HWnd; AMessage, WParam: LongInt;
                LParam: Longint): Bool; stdcall;
var
   s: string;
   i: integer;
begin
   result := True;
   case AMessage of
     wm_InitDialog:
       begin
         SendMessage(Dialog, WM_SETTEXT, 0, LongInt(pchar(Caption)));
         SetDlgItemText(Dialog, idSTATIC2, pchar(Copyright));
         CenterWindow(Dialog);
         //set the application icon...
         SetClassLong( Dialog, GCL_HICON, LoadIcon( hInstance, SFXICON'));
         //save and show the current path...
         ExtractPath := ExtractFilePath(paramstr(0));
         SetDlgItemText(Dialog,idEDIT_PATH,pchar(ExtractPath));
         //fill listbox with all files in archive... (halts if empty)
         FillListbox(GetDlgItem(Dialog,idLISTBOX));
         if AllowSelect then
         begin
           SendDlgItemMessage(Dialog, idRADIO_ASK, BM_SETCHECK, 1, 0 );
           OverwriteOption := ooAsk;
         end else
         begin
           SendDlgItemMessage(Dialog, idCHECKBOX, BM_SETCHECK, 1, 0 );
           OverwriteOption := ooOverwrite;
         end;
       end;