I would like to propose to move the ZipURLInstaller out of the <cargo-*> tasks. Indeed, the installer is something that should be used before calling the cargo tasks (same as when using the Java API).
Thus I propose to create a special task for the installer:
<cargo-installer installURL="..." installDir="..." homeDirProperty="..."/>
where homeDirProperty points to a property that will hold the location of the installed container home.