Trouble ticketing systems and the future
Here's a theory about trouble ticketing systems: they should allow you to submit tickets that are dated in the future, or that only become active in the future.
Here's why. First, it's not uncommon to know now that you need to do something in the future (and further that you cannot do it now). Second, in many environments your trouble ticketing system is supposed to be your authoritative and official repository of known work; if something is to be done, you're supposed to put it in the TT system so that it can be tracked, monitored, and so on.
Now, you can certainly deal with known future events by using your calendar system to leave yourself a note that you need to make a trouble ticket next Tuesday. If that sounds silly when I put it like that, well, yes, it is. It's a workaround, and it also means that your TT system is no longer the complete repository of known work; some of it is floating around in people's calendars instead.
The corollary is that you can't really fix this by providing a tool that automatically submits tickets for people (and then driving it out of your calendar system). This only avoids the absurdity of manually copying information around from calendar to ticketing system; it doesn't make these future tickets actually visible in advance in the ticketing system if you want (or need) to see them.
The reverse corollary is that putting everything into the TT system and manually marking things that can only be acted on in the future is also the wrong approach (although it may be better than calendars in your situation), because it generally clutters up everyone's view with things that, well, they can't act on right now. Most of the time you only care about what you're going to do next Tuesday on next Tuesday, not before.
(Disclaimer: we don't use a trouble ticketing system here for various reasons, so I don't know if good ones already can do this. I polled some people I know and none of them had TT systems that really supported it.)