I don't think there's any point in doing that is there ? If the car is monitoring wheel speed difference and throwing up a warning, then it will already be fitted with a reset button. If it isn't monitoring it then there is no point fitting one ?
It's not like the individual valve mounted pressure sensor systems that are a factory option on more expensive VWs, which I think can be retrofitted (at vast expense) by fitting 4 x sensors and the receiver, and coding the car to recognise it.
You can buy sensibly priced radio-sender valves + display units on the 'net, if seeing tyre pressures is important to a driver, no need for VW branded kit.
Clearly the wheel speed system is a matter of software - I bet the wiring connector is in the loom under the lower console (bar the switch) and the dash lamp is already there. I'd think there would need to be some comms from the ABS controller to the BCM or other system, but any wiring will likely be there. Maybe there is a code to enable the feature, but if not, I'd be wary of changing software, especially if the ABS software needed changing as well...
It may of course be very simple if you know the magic enabling codes, and can push fit a switch!
Steve's suggestion of an aftermarket radio sender valve based system is a much better bet. I am tempted myself. I see kits on Amazon from £25 upwards, which is way less than the price of a single genuine VW RDK sensor ! Very suspicious of the quality. Steve, do you know of any decent kits ???
I nearly bought one for our 5th wheel, but that was 3 years ago (should be compulsory on any trailer!) - they've all changed since, so I have no recommendations.
I did get a bit OCD about the size and weight of the senders (screw in, replacing existing dustcaps) for wheel balance (and also durability) and how long the batteries lasted, but the big thing for me then was to ensure they had the range -- our rig was 12m long, and no easy line of sight, but that's obviously irrelevant for an Up!
I've had several cars with the ABS-based system and it's not bad, but I always forget to reset after I mess with tyre pressures, which annoys me every time!