http://www.aquaboards.com/viewtopic.php?pid=32547
It's possible that it may not work because the trimming removes the hook part of the gynopodium that the male needs to secure himself to the female vent. It may also be the case that heterozygous (HH) high fin genes are leathal to the developing egg.
When I was trying to breed my Lyre Tails I decided to get a high fin male and use him, like th eone in your pic. But it so long to find one that one of my females changed sex and as it was developing its gynopodium it fertilised the other females and I ended up with all the variants of Lyre Tail, High Fin, and normal swordtails.