How to get an onscreen keyboard?

Hello all, I found a second hand Acer Iconia TAB W500 - for those who don't know the beast, it's an X86 Tablet with an optional usb keyboard and relatively modest specs (an AMD dual core C-50 at 1GHz). The fun of this project was to see if a Linux Tablet is usable. It turns out (not surprisingly) that Linux does run very happily on this machine, but that as good as no distribution (that I have found) offers a sensible user interface for a touch screen. Debian stable + Gnome 3 is unusable (stays stuck all the time). openSuSE with KDE 4 looks nice but I could not find a way to get the UI elements in a size usable with my fingers. The best I got yet is Ubuntu with Unity. It's a disaster when it comes to administrate the computer, but it's the best UI for usability. While researching for this project I re-read what KDE 4 devs had said about having to give up KDE 3 because it was not "touchfriendly", so I tried TDE on Ubuntu. Now, TDE is actually very usable on a touchscreen. There is ONE problem - I can't find a way to activate an onscreen keyboard. Ubuntu/Unity starts a tool called "onboard" that works almost as expected (does not always seem to see if an external keyboard is present). It seems to be linked to lightdm. I can try to run Trinity with lightdm. Or has anyone a suggestion as to how to get an onscreen keyboard with tdm? Ah, and there would also be the problem of emulating the right mouse button click. Without this it's very difficule to work in tablet mode. Happy easter! Thierry