I'm not familiar with VideoStudio, but IMO, all pinnacle products are for home users and not pofessional use. The closest thing they've ever done close to a professional product was Liquid... I used it for a time and it wasn't that good anyway.
Whatever program you want to use for this kind of compisiting must have a "chroma key" function/filter. What it does is to substract a color from your clip enablling trasparency. Green and blue are the most common choices, though you can key almost any color, and sometimes you have to do some color correction if keying affected the color of the skin.
Hope this helps... and BTW this forum is not for this topic, and yes, Vegas is far better.