I'm not sure I understand what you want. If you want a specially textured soldier depicting a captive, I don't think the NAM pack has one. If you want one of the soldiers in the Nam Pack to be captive, just do this:
When you want the unit to become a captive, place this in the "On Activation Box" (or in the init box if you want the man to be captive in the beginning of the mission).
removeallweapons this; this setcaptive true