Start/Stop externally loaded SWF

I’ve been looking for help on this all day and cannot, for the life of me, figure out why this isn’t working.

I am loading an external SWF into a movieclip like so:

newMC.LoadMovie (“myswf.swf”);

I want a button to start and stop myswf.swf at will, so I’ve been using this on the button:

on(release){ newMC.stop(); }

I’ve tried some variations but I just can’t get myswf.swf to pause.

If you have any suggestions as to what I should try, it would be deeply appreciated.