From what I've seen on a M43 tunic, you sew them on from behind, and only go through the back with long stitches, not all the way through.
that way, they look clean with no thread lines n holes, but are stil firmly on there
I solved the problem by handing it over to my wife!
Heh, she did it sort of as Neon said, stitching from the back but 'catching' the cloth at the back of the insignia all around the edge, but underneath, so pretty much hidden.
Aye, on the uniform in the stock room, the outer edge is sewn, and then long diagonal stitching following the shape of the insignia was doen along the length for added strength
______________
/ /
/
/______/___
sorta like that, if ya can understand it from text stitches X3
edit: Nevermind, board keeps removing all the spaces x.x
Here you go:
______________
/ /
/
/______/___
I just use brute force with a needle - it doesn't leave any marks. 
You've got nothing to ein, zwei, drei, vier
It's common enough to see them sewn through or done from the back. Both are correct.
'Backed' litzen like panzer or the early bottle green type are easier to do from the back once you have the technique down.
aka Stigroadie
AFRA
better by design
"Truth is a shining goddess, always veiled, always distant, never wholly approachable, but worthy of all the devotion of which the human spirit is capable. "
Backed stuff is easy, heck I did it in the car with Che driving for JohnM on Saturdays journey to Ariel 
the unbacked Late war Litzen is more complex as theres gathering stitches to get the shaping correct. Easiest way is a basic tacking stitch around the edges of the collar tab (diagonal one mentioned). Suprised non of the copydex crew have posted on this yet 
theres nowt so Permanent as temporary
If God had meant for us to sew he wouldn't have made it difficult and annoying and time consuming.
i managed to use my sewing machine to put collar insignia and chest eagle on
Don't talk to me about sewing on insignia, I spent three days hand stitching tunics, great coats and hats at Beltring this year 
Gunnernail, Sticks like nails, Sticks like sh*t ect. all work fine. At a push, Pinkgrip or Gripfill. Downside is that you have to keep both parts of material clamped together, but no problem if you open the can of beer before you start.
Only joking. I sew my insignia on with needle and thead like a girl.
mitermate its the way foward 2 part super glue that sets in ten seconds 
or you give it to your mrs to do as shes much better at it .or in dels case you give to my mrs along with rassbery snaps the sewing that is just befor guy or dave pipes up. 
theres nowt so Permanent as temporary
Only joking. I sew my insignia on with needle and thead like a girl.
some of it
