A slight change of subject here. Attached are some photos of how I've been using flash with my Belplasca for the last three years. This mod has the attraction of being completely reversible. I removed the bottom of the camera and soldered a PC cord to the two solder joints there. The existing X socket has to be removed (and kept somewhere safe) to allow the PC cord through, and the cord can be routed up through the ERC to the top where it can be plugged into the flashgun. The ERC can be closed if the PC connector is positioned just in front of the top cover as shown. The tape on the bottom of the camera looks a bit messy, but it's covered by the case! As you will notice, the PC cord has a PLUG on and not a socket like was originally in the bottom. This is because the PC connector on modern flash guns is always a socket? Seems the wrong way round to me, but that's how it is. Of course this doesn't solve the problem of the Belplasca's cold shoe shorting out the hot-shoe contact of modern flashguns. There were some flash guns where you could switch off the hot-shoe X contact, but the modern ones I've come across don't do that. I can't abide those wobbly hot/cold flash adaptors, so I just took the bottom of the flashgun and un-soldered the hot-shoe contact. This again is a mod that's completely reversible.
Curiously, the Belplasca's red wire in the chassis connection and the blue wire is the switched. At least that how mine was wired. Connect the screen of the PC cord to the chassis and the centre core to the switched.