Change "last Update" date for a specific media id

I've done a lot of searching in the commands documentation, and on-line, so I assume I need an "undocumented" command or command line option to solve my problem.

I've creating records of tapes (using vmadd) into a new master server so that we don't loose track of some tapes that we'll likely never use again, but for legal reasons have to keep around.  I'd like to update the "last update" feild in the EMM so that it shows up with a more realistic date when using bpmedialist against these particular tapes.

I don't need these tapes imported or anything like that, just want to be able to keep track of them, and when they were last updated.

Thanks in advance.