Since you already have both - have you tried running the tablet on ubuntu?
http://gentoo-wiki.com/HARDWARE_Toshiba_Tecra_M4
... the tecra m4 is strongly compatible with linux.
Ubuntu has a whole load of tecra threads...
http://ubuntuforums.org/tags/index.php/tecra/
... but I don't think anyone there has actually collated anything like the gentoo wiki has. The buzz seems to be that edgy onwards has very few problems.
Once linux is installed, you will find it is very likely you can keep many of the tablet functionalities. It may even work better...