Going paperless: request for tip &/or trick

I am considering moving my home office paperless (actually, I am in throes of doing so).

The basic problem I am facing is how to classify papers that I wrote or received in the past, but am scanning today. How do I find “all invoices from 2008?” or “all bills from X for 3 years?”.

Right now my scheme is to set up folders that more or less match my paper filing system, and then to have tags “2010”, “2009” etc. to indicate the tax year associated with that document. But (a) I’d like something more fine-grained, and (b) it requires that I remember to tag every incoming document. I really would like to be able to set a date stamp for every document, different than the file’s creation date or modification date.

TIA

I think I answered my own question: http://www.devon-technologies.com/scripts/userforum/viewtopic.php?f=4&t=9016 implies that what I need is planned for the future, but is not yet available in DT.