Xailer & OZ Software

Hello!
I want to make Value property in TCombobox class which have the same value
as nIndex property.
I did it like this:
--------
#include "Xailer.ch"
CLASS TCOMBOBOX FROM XCOMBOBOX
PROTECTED:
METHOD SetValue(nVal)
PUBLISHED:
DATA bBlock
DATA xEmpty
PROPERTY Value INIT 0 READ ::nIndex WRITE ::SetValue( nVal )
ENDCLASS
METHOD SetValue( nVal ) CLASS TCombobox
::nIndex:=nVal
RETURN Nil
--------
but when I try to access Value property it is not found (error).
Can I achieve this?
If I use PROPERTY clause without READ/WRITE (PROPERTY Value INIT 0) it
works.
Thank you.
Oleg.