How to make a second uv in the 3ds max?

I have a uv set.But it seems that 3ds max doesn’t allow me to create another.I am a little confused about it. Please explain to me.Any answers will be appreciated.Thanks!

Hi !!

This tutorial will help you with that:

Is for UDK, but works for UE4.

Enjoy!!!

Thanks very much!That’s really what i want!!