The best way to troubleshoot rc-switch


I want integrate a 433Mhz siren in to Arduino (specifically the Arduino present on the BeagleBone cape that ships with the Ninja Block) so as far as I can tell this is all about rc-switch (warning big phone cam images):

There is an atmega48v on there, the RX says 9931A on the PCB and has a cd4069ubm hex inverter being used I assume for the receiver.

Basically I have the remote and the siren, the remote actuates the siren, rc-switch sees the button press as a 24bit code, I can see it but when I try to use the code to actuate the siren using rc-switch nothing happens, I believe RX and TX are implemented in different parts of rc-switch and so there could be stuff that RX OK but that doesn't TX properly?

I really want to get this to work but I have no idea where to start, I have access to a scope, logic analyzer and sdr as well as lots of Arduino boards and breakouts including 433Mhz, can somebody point me in the right direction please.