This is very easy. No shots fired.
Think Berlin wall crossing. No one made it if they were spotted. It was a sure way to die just running the wire. So here goes , the first mission done right.
Immeadiately go in to combat mode. You will have to manually go into combat mode at the begining of every turn, if you are not spotted, That should be every turn you are on this map. Note this is before the tank incident. You need all the time you can get to set this up.
The first thing you will do is spend a couple AP's to get your inventory in order. Put the wire-cutters in the use hand and a hand grenade in the other.
Go into hide mode.
Move up the side of the map.
Crawl up to the fence if you can rest there while not being observed. This takes two or three turns. Remember to go into combat mode manually.
Now you are in posistion to cut the wire right after the cut scene tank event.
End combat mode til cut scene appears.
Comming out of the cut scene , go right into combat mode manually.
Cut the wire crawl foward cut the second wire.
Keep it in combat mode and stay in hide mode crawling on your belly.
Crawl up to the second tree.
Staying in combat mode. Get into run stance mode. You should still be hidden if things are going right. No one has seen you yet.
Spend a couple of AP's to be ready for mission 2 at this point. Put the wire-cutters away and equip a pistol or sub-machine gun in its place. The grenade is the first thing you need in mission two. After tossing that a quick firing gun is the next thing of need.
OK, back to combat mode running to the border from here. It takes two turns so be sure to go into combat mode as you do it.
I hope that helps all those struggling to get started. And those replayers that dread the opener.