I've not seen it done on a Flamina...
The method, as such, is to find some wheels with good middles and rotten rims (typically those rolled edge type that rust from the inside), cut the rims off, and weld into the rims from a Rover P6 or whatever it happens to be. Various people have done it over the years but these days its probably only Tim Burret. His "extra" is to drill cooling holes before removing the original rims so he's left with neat semi-circles where the centre joins the rim almost like spokes.
This is his car. Click on the photo to zoom. Hand welds?
http://www.lancia.myzen.co.uk/forum/index.php?topic=4305.0David