If you have a lot of these, you may want to create something like an @waitingforlongterm that you only check monthly...OR (and this is what I typically do), if you know for sure you don't need to be reminded about this at all for awhile, create a ticker for yourself during a more relevant time period.
If you handle your GTD stuff electronically, I think the best way to do this in Outlook this is to send yourself a post dated email - then you can just drag it into tasks and categorize it as WF.
To do this, write an email to youself, then select, tools, then options and enter the appropiate date in the box called "do not deliver until" - then it will show up in your in box when you need to see it.