Hi there. We don't currently have a similar piece of hardware here, but I'm assuming that the Free Edition does not allow you to use pressure on that machine? We use wintab, which is a pretty standard way of accessing tablet devices. Ink services in Windows Vista and on Tablet PCs are also supported.
If you're not getting pressure it may be that there's a driver incompatibility, but it's also possible that there's a more straightforward cause so it would be worthwhile emailing me at firstname.lastname@example.org with your operating system and computer make and model so I can check a few basics with you just in case.
At the very least, if it appears to be an incompatibility I can note it down for future reference and consideration.