Modify Inductive Sensor (Dakota DCPT-4000)

I have a Dakota DCPT-4000 inductive driveway sensor.
However it does not operate in the way I expected and I do not want to use their
built in transmitter as I do not know their protocol, etc.

What I want is a relay that is closed when the sensor is activated.
I'd like to modify it to work in a wired fashion.
It may be simplest to connect to the antenna of their transmitter to detect when it
transmits to activate my relay circuit.
A better solution to switch my relay on when it senses metal and then go off when the vehicle has passed.
There could be times the vehicle stops right over it.
Please comment.


Please comment.

I have found a partial solution to this.

When the sensor is triggered, connector J2 goes high to 9VDC for about a second.
The red and black wires attached to it are connected to the transmitter.
Since I do not want the transmitter in this case for me, I disconnected the two wires
and connected a NO (normally open) 5VDC coil reed relay to it.
I can now connect the relay to my transmitter.