If you want to give Nightvision in Zombie Plague then sorry, but it's impossible, hardcoded ZP nightvision will override yours.
If you want to give nightvision and it's not related to Zombie Plague, you can send nightvision messages. Here is example from ZP:
PHP Code:
// Game Nightvision
set_user_gnvision(id, toggle)
{
// Toggle NVG message
message_begin(MSG_ONE, g_msgNVGToggle, _, id)
write_byte(toggle) // toggle
message_end()
}
toggle = 1/0
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