[Inkscape-user] Custom Font Issues

Hello! I'm new to Inkscape, and I'm having some problems finding custom fonts.

In the Style selector of the Text and Font Dialog, it only displays normal, italic, bold, and bold-italic. I'm using a custom font whose weight is "light" and another that's "black," but these two are not options in the Style selector. It seems like Inkscape is guessing at which matches best, but it's guessing in the wrong direction. Is there a way to explicitly specify the font to use, or to add new items to the Style selector list?

Thanks for your help! Ryan