Last stand pro challenges

[EwaldCH]

Please,can you help me with some tips for getting the last stand pro challenge which requires 20 kills to unlock.
Also,there is a last prestige challenge which requires 200 kills in last stand.
These challenges seem impossible to me.

[Pure & Rustic]

The Perk Last stand: Get the kills when you are "In Last stand" ergo: wounded and down.
The prestige Last stand: Get the kills when "using" Last stand perk. All kills count.
The Perk:
Challenge: "Last Stand Pro: V"(lvl41) - Kill 50 Enemies while in Last Stand
Challenge: "Last Stand Pro: VI"(lvl41) - Get 100 kills in Last Stand.
The prestige:
Finish Last Stand Veteran IV - 100 Kills while using the Last Stand. Not 200 kills
You can also get some more achivements when using last stand, like last kill, last kill with c4, or the last kill with semtex, just try out and see whats you preferd wapon, nades or akimbo G18's or whatever you like. You have to be above a sertain level to use main weapon or sidearm, otherwise its the pistol when you get down in Last stand.