Actually, they act as an instrument, not as a skill modifier. So, attach a wind augment to your breastplate and essentially you will always have a wind instrument equipped so that you don't have to equip one for invis. All of the augments have an instrument modifier, but most of them are lower than any mod you would get from an actual instrument. Still, better than nothing, especially if you are non-epic.
Rhapsodde Enbleu
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