windows 8 - Use touchpad while "typing"?

My laptop (a Sony Vaio on Windows 8) disables my touchpad when I "type". This means actually typing, or just holding down a key like say, W, A, S or D. The touchpad stays disabled for a short period (<1s), after releasing all keys. Naturally, I want to turn this feature off.
The touchpad uses a Synaptics driver, but I can't find a setting anywhere to enable the touchpad when typing.
I found values that allude to this functionality in the registry (e.g. HKEY_CURRENT_USER\Software\Synaptics\SynTP\TouchPadPS2\ZoneManager\TPTyping - Enabled), but their value is always 0, so I reckon it must be coming from somewhere else.
I've tried reducing the touchpad's sensitivity, as I read somewhere that there that certain values might secretly activate the "palm detection" functionality, which in turn secretly activates the "disable then you type" functionality, but to no avail. (Yes, I already went quite deep into the rabbit hole.)

Edit 14-11-12: I've updated the Synaptics driver using the one from the Synaptics site, but I still don't have a setting to enable the touchpad whilst typing. (Neither do I have the "PalmCheck" settings.)

Edit 27-11-12: I've gone back to the original driver, as the generic one had too many issues for my liking. This version doesn't have PalmCheck either, but like the generic one, it does have something called "SmartSense". Apart from the name, it looks like PalmCheck. Turning it off however, did not solve the problem.

Answer

Since disabling SmartSense didn't solve the problem for me, I had to dig a little deeper.
After much toil and bickering with various forms of Sony Support, I gave up and tried messing with the Registry. After some failed attempts to disable the Synaptics filter driver that's attached to the keyboard, I found something that worked.

Solution:
In the Registry, go to the key HKEY_LOCAL_MACHINE\SOFTWARE\Synaptics\SynTP\Defaults, and set the value of all string entries of the form PalmKms…, to 0. (Of course, they probably don't all need to be 0, but have fun finding out which one(s) you actually need!)
These values determine the amount of ms that the touchpad stays disabled after keyboard input has been detected.

I think Sony will probably issue an update to the VAIO Control Center where you can simply disable this functionality, but until that day, this fixes the issue.