Anchoring navigation to resizing movieclip

hey ya’ll

i’m trying to do something which is probably relatively simple. however, i’m having big troubles figuring it out.

i want my ‘navigation’ movieclip to stay anchored to the left hand side of my resizing ‘box’. so that when the box resizes, the navigation moves along with it.

if anyone has any bright ideas i would greatly appreciate it.

many thanks,
_grennex