Resizing armor; Invisibility issues

[Elseria]

So I've been trying to resize this hat to fit around my character's hair: http://www.loverslab.com/showthread.php?tid=4158&pid=296981#pid296981

 

I've tried resizing it through 3ds Max 2012 and also through the edit tools in NifSkope; however, I've been coming across this issue where the hat will disappear when the camera is close to the character. It works fine at long distances.

 

This is the modified nif file I tried to use: http://www.mediafire.com/?5xs52jdzs4fr71t

 

My knowledge of modding is extremely limited, so any help would be appreciated.

 

EDIT: Got around it by copying the NiTriShapeData from my resized nif and pasting it into the original nif file. I still don't know why resizing it would screw things up, but that's irrelevant for me. I am now hitting my head over how simple the solution was.