Hi Gerd,
I don't know NI's official stance on this, but if you:
1. do a distribution for reasonably powerful embedded devices (meets minimum system requirements)
2. deploy full Win32 API as part of the embedded build
3. have no problem running your app in 'big box' XP
then, theoretically you should have zero problems.
And historically, the same was true with NT embedded and NT, again, regardless of NI's official stance. Now, if you are trying to run your toaster with XP embedded, then you are on your own. Maybe you should be using a Unix-type distribution if you want to do that--but I digress.
I have been successfully deploying CVI to NT4 embedded devices (specifically industrial touch screen computers on moving machinery) for almost 5 years now. I will soon move some of those same apps to newer XP embedded touchscreens. Perhaps it is nieve, but I have no anticipation about the move. Since NI doesn't officially recognize the embedded distributions of Windows, you may be on your own. To say that another way (so others in this board don't pounce on my post), using undocumented or unsupported features is beyond the scope of NI's responsibility. If NI changes something in their next CVI release, it may not work anymore.
Good luck,
Orlan