I Dont know much about Vietnam :P this is just some info on how to replace the chin straps and slings.
You know the Tie downs on the legs of some DML Vietnam pants? Just cut the threads that attaches the tie downs to the pants.
(Thanks to everyone on this forum who have done this in theyre kitbashes or suggested it)
NOW! lets say you want to Make a replacment Chin Strap instead of that crappy elastic.
Just cut the thread that holds the elastic to the helmet and attachment clips and mesaure it beside the Tie downs and cut the right side. now you need fabri tac (you can get it at wal-mart in the craft isle)
What I did for my chin strap was use SOTW Clips from one of theyre vietnam helmets (They look pretty good)
Now what I like to do to the ends of the Tie downs is quickly move a flame from a lighter over the end so it doesnt fray. Then just put it back together with the helmet clip like it was before with the fabri tac but instead of the elastic use the Tie downs :P
It may take a few tries to get the Chin strap to fit and it to fit the figures head right but youll get it to work
you can also use it to replace the elastic thing that goes around the cover of the helmet.
Tie downs can also work as slings Just take off the elastic sling and replace the elastic with the Tie down with fabri tac and the metal peice from the old elastic sling.
You can also Use the tie downs for other things. But thats all Ive done so far :P I Might replace some of the plastic cloth on the figs equipments.
Heck if I can do it! Anyone can!