haddock depencies to std-modules

hello I use haddock to create documentation. Everything is fine except of the references to standard modules. If I am using standardtypes like Int or String haddock wants to create crossrefs to these modules and fails because of missing "sourcecode". Is there a simple way to fix this? I've heard of interface files to create right refs to existing docs, but that doesnt work. Whats the right way? Cheers Patrick