Certainly not possible as the traction control mechanism on the Astra GSi is controlled by the C20XE ECU and its wiring loom. All it does is close a second butterfly in the inlet manifold electronically. This is located under the main inlet manifold butterfly controlled by ya foot. So in effect its not proper traction control, just a way of shutting off the engine power in tune with the signal coming from the ABS.
The only way of having traction control with the C20 LET is by fitting an aftermarket unit such as racelogic etc.