Scripture Marking: Colors?

This might be a stupid question, but how can I change the colors used for marking scriptures? Actually, I only need one extra color: orange. 4 colors are not enough... Is there a way to add a color? I am on an iPod touch, most recent model, but not iOS 5 yet.

Thanks in advance

On that note, if it is not possible, would it not make sense to have the standard colors for the app be those used in Preach My Gospel, since it is an official church publication that ties a color together with each lesson of basic church doctrine?

Blue - The restoration
Orange - The plan of salvation
Green - The gospel of Jesus Christ
Purple - The commandments
Yellow - Laws and ordinances
(Red - Recognizing the spirit)
(Pink - Christ-like attributes)

Without suggesting that people always use these colors for these topics, could I suggest that if it is not possible to change colors in the app and have as many as you want, then to at least have these? (Those in parenthesis are optional.)

Thanks I really hope someone will answer this question.