Add Octave Interval should use same spelling as base note

When you add an octave interval above (or below) a note, the added note sometimes gets translated to the current key instead of using the spelling of the base note.
Steps to reproduce:

1. Create a new score with Bb major (two flats) as the key
2. Start note entry (N), and enter a D# note
3. Add an octave interval above (Alt+8 or below (Shift+8).

Expected result: The added note should also be a D#
Actual result: The added note is Eb

(tested using r2006)