Unfortunately the method I use relied exclusively on Corona's vector display objects (newCircle, newRect, newPolygon, etc.), which are not aliased (at least not yet). So if you need a softer edge, then I think your own workaround is probably the better bet, at least for now.
I took a look, and I couldn't find a feature request for anti-aliased vector objects. It's probably worth making a request and trying to drum up some votes for it (I'd throw a couple votes at it). You can make a new request here: http://feedback.coronalabs.com/forums/188732-corona-sdk-feature-requests-feedback