That method is simple though it needs a few specially made parts.
I think I made it even less complicated because all parts I use 
are standard parts which you can easily find at any hardware store
or baumarkt.

All you need is :
an M8 bolt with cone shaped head (I used a bolt of 50mm long but
it can also be longer or shorter).
an M8 nut
a metal washer that fits the M8 bolt
and a nylon washer that fits the M8 bolt  -
the nylon washer is to avoid scratching the outside rim of the eylet
(this just costed me 1,05 Euro)
 
METHOD:
put the eylet in the hole in the drum shell
put the bolt through the hole, from the inside to the outside
put the nylon washer on the bolt (outside of the shell of course)
put the metal washer on the bolt
put the nut on the bold
 
Use a screwdriver to hold the bold inside the drum shell
Use a spanner to turn the nut on the outside of the shell
After using some force the cone shaped head of the bolt forces the 
inner edge of the eylet outwards (just like the metal ball would do 
when hitting it)
Go easy on turning the spanner - small steps at a time and check
to see if the inside rim of the eylet is bent enough already - 
otherwise give it a little more force
 
Advantages of this method:
you can also use it on small toms (there's no room (or not enough room) 
for using a hammer inside a small tom)
the risk of damaging the outside is minimalized 
(with the hammer method you have to protect the outside of the tom)
no risk of damaging the inside of the tom 
(which can happen of you miss the metal ball using the hammer)
 
On the pictures you see the parts I used as well as how they 
should be used on the drum.
 
I used this method a few times now and from the first time on the result 
was perfect - I can not even see the difference between an original 
installed eyelet and the ones I did.
 
Please feel free to use this information and pictures on your webside.
 
Good luck !
 
 
Gijs van der Plas
The Netherlands