Some song lyrics in the official lyric book that accompanies the CD is sung as another word. Usually, the way it is sung is given as a furigana on the kanji: Written: 君が希望に変わってゆく ...
I've seen some kanji whose furigana is actually katakana. For example, see the following manga cover for 桜蘭高校ホスト部. When would a kanji character ever be pronounced as a loan word?