[Vala] avoid "method never used" warning for methods linked to Glade files in private class

[rastersoft <raster rastersoft com>]

Hi all:

I need to create a class with several methods that are used as callbacks 
for buttons and other widgets, but they are defined in a Glade file.

When the class is public everything is fine, but when I declare it as 
private (which I need for several reasons) I receive a "method 'XXXX' 
never used" warning.

How can I avoid those warnings?

Thanks.