Need help with LX7007Compact connected to FLARM

Ok - this one is for all of you flight computer savvy guys in US-glider land because I for sure am at the end of my whits.
Here is the set-up:
I bought a used LX7007Compact. This is the one which does not have its own GPS receiver, so it needs an external source.
I also do have a PowerFLARM core which is/was feeding a Butterfly 57mm panel mounted display. The core is working fine - I get the two green boxes.
The LX is supposed to be connected to the FLARM core using the same cable used to run the Butterfly (8-pin to 6-pin) and both - the LX and FLARM - are supposed to be set to 19,200bps.
The LX is consistently displaying the warning 'No GPS data received'!
In an act of desperation, I hooked up my stone-age LX20 logger - same results! Only if I change the LX20 and LX7007Compact to tx/rx at 4,800bps will the LX7007Compact acknowledge receiving GPS data. If I interpret the FLARM manual correctly, no traffic thread info is transmitted at the 4,800bps setting, so that seems to be not the right way to do it.
The whole idea of using this set-up is to free up panel space and to get rid of the PDA and cables since the LX7007C does display the FLARM warnings just like or similar to the Butterfly does.
The LX7007C has been back to the factory and of course, it works flawlessly on their bench - go figure - but I have to take their word for it!

Question(s): does anyone use a LX7007C/FLARM combination successfully? If so, what are you doing differently? Is there perhaps something that needs to be set differently in the FLARM config.txt file?

Any serious reply is appreciated!

Thanks,

Uli