Unfortunately, that kind of functionality is the responsibility of the device manufacturer, not the office suite programmers. It works with Office programs because it was designed to work with Office programs. OOo will run on your tablet PC because you're getting WinXP, but whether the pen works is a different question.
Please do check with them and let us know what they say. Someone else a month or two ago was asking about using OOo on a pen-tablet system too, so there is some interest in it.
Maybe if OOo isn't already supported, you can give them a nudge and suggest that OOo has a global reach and is increasingly used by European governments, so would be worth supporting just to keep itself visible in the market share of users who are abandoning Office.