If the guitar part is actually the BB Guitar or a melody part, you can edit the guitar chords in the BB edit program. Just add the voicings or the higher notes on top of the notes you have (upper register of the staff) for the chords and delete the lower ones. Be sure not to add too many notes as this will muddle the guitar sound. Just try adding one note and deleting one note at a time and see how is sounds. This should give you a higher pitched guitar sound. If you don't know what the upper notes should be, you can use BB Chord Finder and it will give you several voicings of the same chord. Hope this helps.