Wait a minute...
How is the signal being re-routed to the main antenna on the radio?
It would require some major board-level modification to the spektrum module itself in order to do so electronically.
Unless you simply drilled a hole in the back of the module, and also through the case of the helios and routed an extension wire for the standard spektrum-type antenna inside the radio.
Hmm...so how was this done?