Hey Yella,
Fit new ones to mine a while ago and what I did was to wrap some thin but strong twine around the bit that goes through the hole, only wrap once, then I put both ends of the twin through the hole and while applying pressure from underneath I pulled on one end of the twine and by doing that the plug pulled itelf on, a little vaseline might help, but only a little.
Cheers
PNYGTA