Promax remote switch in combination with 433mhz transmitter

[Bram]

Dear all,

I just got started this weekend with a bound to be new hobby. I've bought a Raspberry Pi 3 and some supplies like a 433mhz RF link kit. I've also attached picture of the transmitter and receiver in the attachment.
I have now followed many how-to's and search a lot online but I don't seem to get my ProMax remote power switch to work with my setup. It is the Promax version as discussed in this thread.

I have installed Raspian, Domoticz, WiringPI and a lot of things as recommended in various how-to's to get connection with my power switch (e.g. link, link2, link3). I have the RFSniffer as discussed by Ninjablocks working and I can pickup the signals of the Promax remote. But when I send these same signals with the sendcode action in the terminal then it is not working (let alone via Domoticz).

I'm wondering if there is anybody who has a working set-up with the promax switches and the simple 433 transmitter. Or if someone could point me in the right direction in the form of a tutorial or how-to.
Another thing I'm wondering if anybody gets the promax switches working without using the RFXcom module. I'm willing to invest a bit more but I think the RFXcom module is just a bit too expensive since I first just want to experiment a bit for fun. I read a lot about the RFlink gateway, maybe someone has the RFlink and the new promax working?

Thanks in advance!