[villagetinker]

It is possible to treat the corrosion. Stop by any boat store, ask about treating corrosion. There are a variety of products, I recently used a zinc based product for corrosion on an aluminum body panel on my car, is fine after a year of sitting outside. A word of caution, do NOT use an iron or steel based tools on the aluminum, use BRAND NEW stainless steel brushes or wire wheels to clean the area, then apply the zinc (or similar) based primer, then typically a base primer suitable for your final color (white for light finishes, grey for medium, and black for dark finishes). After all had dried, apply the final finish. You should be able to get primers that are compatible with the finish paint.
I hope this helps, if you are not a do it yourself type, this will at least give you some background if the party you hire suggests painting the area.