including FA21RF smoke detectors into arduino smart home project

Dear all,

thanks to the forum I made it already to automatically switch on an off lights and also sockets with the RC switch library. (receiving standard senders with 433MHz and then send the same signal).
Therefore I wanted to go on with the next step to also include my new bought smoke detectors whom can be connected with each other over RF 433MHz.

Link to the datasheet: http://downloads.cdn.re-in.de/1200000-1299999/001274875-an-01-ml-2ER_FUNK_RAUCHMELDER_FLAMING_de_en_fr_nl.pdf

I thought I can also get the signal from them by using the RC switch library but it did not work. No matter if I pressed the learn button which normally should make the detectors to connect them neighter when I pressed the test button on one (which the others acknowledge with blinking LEDs).
There was no signal captured.

Can anybody help me / Did somebody of you implemented those detectros already?

The final stage of the project will then be to send me messages onto my mobile phone if one alarm goes off but if I can't connect the detectors I don't need to investigate this.

Thanks for your inputs!
J