Change Portfolio Template to 4-columns

Guys –

I’m using Pinboard and I did not build a specific page for my portfolio. Instead I just designated a category in Appearance/Theme Options/General/Portfolio Page.

The portfolio works exactly as it should, except that I can’t set it to use template-portfolio-four-column.php.

Instead I am only getting three columns. Anyone know how to control the number of columns it returns without setting up a specific Page? (That would require me to rejigger the navigation of the whole site).

Thanks a lot,
Zach