With the touch-panel you can use both,
I still use the old 3.3.6 because I have no real need for the new features coming in 4.x. The rest of this section is about 3.3.6-related issues.
I would recommend using my XF86Config, which is running the Display with a 16 bit 800x600 resolution. Just copy it into /etc/. It is made for using none external pointing-devices. Get the touch-panel-drivers and compile them, then copy the module xf86B112.so to /usr/X11R6/lib/modules/. 1
If you want to use an external PS/2-mouse with the touch-screen, I can give you no real advice. I started configuring the track-point plus an external PS/2-mouse with sax -server vga16, but had trouble with the mouse-port: you should use /dev/psaux for this configuration. Don't forget to make proper settings in the BIOS Setup.
I think it is the most comfortable way of working, if you get an external USB-mouse as I did. Then you have three pointing-devices at the same time. In this case continue reading ...