There is another thread here on sort of the same issue.
We don't have any built in functionality for this. It seems to me it would be possible to use an owssvr.dll connection to get the ID for the item in the document library, then use SubmitToSharePointList to basically submit the metadata (although you'd need to manually create the mapping, since the mapping tool doesn't currently let you select a library - or, you know, I could change that in the tool and get you a new build...)
Another option could be to just use list items with attachments instead - you can have the same qRulesLink / qRulesFilename functionality with that - here's a blog post on the 4.2 version.