First of all ... the LF2 Nightie is a PROP, because it shows in the prop menu up top. You've been told multiple times that PROP figures DO NOT CONFORM. 

I am not going to give the instructions here again. You've been told many times how to attach PROP clothing to a figure.  You really do need to get yourself organized and bookmark topics that have already been answered.  It's expecting too much of users here to answer the same question multiple times.

/ grumpy old lady rant off