i'm texturing a plane on papervision 3d and i tried several settings with no avail, text looks bad anyway. Here's an example:

this is how i make the material:
var mc:MovieClip = new MovieClip();
var txt:TextField = new TextField();
txt.width = 650;
txt.height = 450;
txt.multiline = true;
txt.wordWrap = true;
txt.selectable = true;
txt.text = "<center><h1><b>May i have your attention?</b></h1></center>";
txt.antiAliasType = AntiAliasType.ADVANCED;
mc.graphics.beginFill(0x000000);
mc.graphics.drawRoundRect(0, 0, 700, 500,15);
mc.graphics.endFill();
mc.graphics.beginFill(0xFFFFFF);
mc.graphics.drawRoundRect(25, 25, 650, 450, 15);
mc.graphics.endFill();
txt.x = 25;
txt.y = 25;
mc.addChild(txt);
var mate:MovieMaterial = new MovieMaterial(mc, true, true, true);
mate.doubleSided = false;
mate.smooth = false;
mate.tiled = false;
mate.interactive = true;
this seems to be a problem with resizing. How does texture size works on pv3d? Any help is appreciated.
Have a look at Andy Zupko's post on Text in Papervision.
And also have a look at VectorVision as it is integrated in Papervision.
Based on your setup you can pick the solution that works best for you.
Also bare in mind that Papervision hasn't been updated in a long time and might not be any time soon so it's worth exploring other 3D APIs like Away3D.