Insert arbitrary (non-Unicode) glyph in XeLaTeX

I am creating a LaTeX template to my University’s standards. The official OpenType font "UnB Pro" (freely available at http://marca.unb.br/fontesunb.php) has a special glyph to insert the logo. This glyph has no Unicode number (not even in private use area) according to FontForge, but it does have a name, <ass_completa_CONT>. How can I use it in LaTeX?