the varnish must be removed from the tip of the tail where you intend to solder it or connect to it or you will not get a good connection. Placing an insulator over the tail is recommended by many here
As for connecting it, I've seen several ways. Where the windings need to be connected together, you can solder them and then insulate the connection. The connection gets imbedded in the resin when you mold the stator (this seems to be common).
Where the connection is made between the tail and the cable leaving the generator to your rectifier, I've seen bolts mounted through the resin in the cast where you have free space, then the tails and the cable are terminated at the bolts. If you do this, use bolts that will withstand the elements and not rust or corrode (I'd use stainless, even though it's a dissimilar metal). Don't forget to strip the varnish off where you connect it.
If you look around the site, you can see pictures of what others have done.
