Is it possible to customise Menus and Toolbars of extensions delivered as .oxt files?

I have developed a number of extensions for LibreOffice Writer, all have both Menus and Toolbars which work happily, however, when I go to

Tools->Customise and choose either Toolbar or Menu, my extension Menus and Toolbars are not shown.

I would like to offer people who use the extensions the ability to adapt both the menus and the toolbars.

Is it possible to have them added to the Tools->Customise function by using certain entries in the .oxt configuration files and if so what are those key entires and in which files?