I've recently begun using NYDITOT
http://www.softmaker.de/nvd_en.htm on my X5 and so far so good. You do have to soft reset to change to/from landscape mode, but it seems to work well with textmaker, planmaker, and phatnotes (my three most-used data entry programs). Oh, and fine to date with PIE, too. It is not cheap (well, it is if you buy it about 11 November), but maybe what you are looking for.