can we use -ve RBearing for glyph

Hi All, I am facing strange problem, in Lohit Project Kannada, Telugu script font has many glyphs with -ve RBearing, typesetter used this to satisfy script requirement, i.e when two glyphs come together they should looks perfectly adjust. But in Gnome Desktop in some Labels and Menus Rbearing -ve part is getting cut (not getting displayed) http://pravins.fedorapeople.org/kn_IN-Bug_GnomePanelProblem.png see third word with yellow mark Can someone guide me, should we fix it in fonts or in rendering engine or somewhere else? redoing type setting is really big task Thanks, Pravin S