Windows 10 touchpad driver

[JesseKnows]

Hello,

I am trying out Windows 10 Technical Preview (build 9926), 64-bit on a TP 61 (7663-12U).
I installed the build as an upgrade from a running Windows 7 SP1 installation. Everything seemed fine and the system is stable. Fingerprint Reader still works.

Regarding drivers, I have an observation and a problem.

After the install, the display (nVidia Quadro NVS 140M) was running under "Microsoft Basic Driver". Selecting "Update Driver" in the device manager caused the system to fetch and install the nVidia driver.

The system is running with the Thinkpad UltraNav touchpad driver, version 16.2.19.13 which I had running in the Windows 7 install. The only scrolling option there is one finger.
I want to enable Gestures (e.g., 2-finger scrolling). I tried to install the Synaptics driver (17.0.19 from the Synaptics web site), and the installer fails without saying why. Telling the Device Manager to install the driver from the driver folder causes an error saying that the INF file is not signed.
I tried running the driver's Setup application with Windows 8 and with Windows 7 Compatibility, did not make a difference.
Other than disabling driver signing, is there anything else to try?

J