Depth Help!

Hello,
I’m having trouble making a movie clip (portfolio_mc) appear on top of another movie clip. (bg_mc) I’ve tried setting portfolio_mc to the next highest depth using the following directly on the movie clip.

onClipEvent(enterFrame) {
this.swapDepths(portfolio_mc.getNextHighestDepth());
}

I’ve also tried multiple times to set bg_mc to the lowest depth possible, but my novice AS skills are hopeless.

Are there any other ways I can set portfolio_mc’s depth to the highest possible?
(or bg_mc’s depth to the lowest possible…)