[Haskell-cafe] HackageDB Question

How does HackageDB generate the documentation for uploaded packages? Specifically, if I am using my own build system rather than Cabal, then what do I need to do (e.g., what interface do I need to supply) for HackageDB to correctly generate the documentation? I've glanced through the source code posted at http://darcs.haskell.org/hackage-scripts/, but I am having trouble finding the code which generates the documentation. Thanks! Greg