[TJ Paint]

The aluminum is oxidizing. If they are just wanting a 'low price/ quick fix' then grind/ sand the problem areas to get all the loose paint back. Then sand the aluminum until all the oxidation is gone (it will look shiny). You can then paint it which ever process it is that you use. A one step deal would be http://www.benjaminmoore.com/bmpswe...atalog/product_pages/paint/prd_z163&_pageLabel=fc_productsspecs#recommended_for

(I would still use stix or some sort of proper primer with the above)

You could also use Stix to prime first then any of the following:
http://www.benjaminmoore.com/bmpswe...r_1_10np=productcatalog/product_pages/paint/prd_164&_pageLabel=fc_productsspecs

http://www.benjaminmoore.com/bmpswe...r_1_10np=productcatalog/product_pages/paint/prd_363&_pageLabel=fc_productsspecs

http://www.benjaminmoore.com/bmpswe..._1_10np=productcatalog/product_pages/paint/prd_c163&_pageLabel=fc_productsspecs

i wonder if there's a waterborne superspec dtm like the alkyd you posted a link to.