For that....if you wanted the text to remain a vector that's a little harder.
You might be able to simulate that, depending on the font you chose, but PSP does not have the ability go blend between the stroke and the fill. It can create a gradient based on the fill and stroke colors but having them seamlessly blend between the stroke and the fill is harder. Also the radial and sunburst options maintain their shape and don't conform to the shape of the gradient. So the "O" would have to be a perfect circle to get the best effect.
One option that might be of use to you is the layer style "Inner Glow." I don't know how well it will work for what you want but it could be worth looking into.
Inner glow creates a "glow" effect (essentially just a smooth gradient based on the color you choose) from the outside portions of the layer, inward. On layers that have a lot of transparency, like vector layers, this keeps the glow confined within the letters or drawn area of the layer. Of course layer styles in PSP aren't all they could be just yet. So you have two very basic sliders for determining the appearance. Size, and Opacity.

- GradientO.jpg (16.83 KiB) Viewed 4218 times
In the example above they use the same Inner Glow setting for the layer style but the one on the left has the stroke turned on while the one on the right does not have the stroke turned on.
If you were willing to work with Raster Text (Text you can't edit as text anymore) there might be more options but I would have to do some experiments to find some options as I don't know of any off hand.