Two problems making speech balloons

I'm using photopain* 9, and honest-to-god have exhausted every idea I can muster in trying to get decent, clean speech balloons (for comics and the like). The best way I've found is to create the shape of the balloon as a mask (that is, an ellipse and a triangle polygon), create a new object, and use the "stroke mask" button on the brush tool to draw a line around the edge of the mask. Unfortunately this creates two problems:

1) The border is just RUBBISH. It is rounded all over, rather than having the sharp, clean corners where the triangle part intersects the ellipse. I'm guessing the way the stroke mask tool works is pretty much the same as creating a path from the mask, then stroking the path... since I noticed that creating a path from the mask made the same ugly curved corners, not having enough nodes or whatever. Is there any way I can get the program to tighten things up when I use the stroke mask tool to create a proper border around the edge if my mask?

2) Even when the border is in place, I have trouble applying a fill on the inside. Because the area inside the border is still transparent, when I fill there it doesn't fill the anti-aliased edges of the balloon. Surely there's a way to prevent this? I did find a workaround where the object I create the balloon in is already filled white, and I cut the white away from the outside edge of the border, but this seems laborious and time-consuming. There must be a better way.

Or perhaps I'm going about this all wrong anyway. Is there a quicker solution to get nice looking speech balloons in Photopaint?

*This was originally a typo, but I left it because it was somewhat apt.