Is there a way to change the "Created" date in the Summary Information property tab, on parts, assemblies, and drawings?

I have created a new sheet format, with all relative information linked to file properties.  For all newly created documents, this works fine.  We have tons of very old drawings with manually filled out title blocks.  When we have to "touch" any of these, it is our std practice to update the sheet format with the latest linked sheet format.  Most of the time, this works fine as well.  However, for some reason, many of our old files have this "Created" date field all fouled up.  For example:

I think the reason these files are like this has something to do with when they were imported into our PDM vault, when it was originally setup.  It doesn't really matter to me why the dates are messed up though.  I just want to know if there is a way to fix it.  Does anyone have any ideas?