Did it a bit different, but probably with the result i wanted.
In the repeaternode sketch I used the following line:
This created a repeater node with node-id 4 (just an arbitrary number)
In the Dallastemperature example I used:
This created the sensor node with id=5, talking via repeaternode 4 to the serial gateway. This works. See the info from the temperature sensor being relayed to the serial-gateway.
I haven't tried the method you suggested yet, but this sounds interesting of course. Wiil do that after Christmas I think.