Oh, my bad, I thought you said no javascript.
I've also since this behavior around, but it's been a while (in the Web 1.0 era).
with ajax is the same thing as using curl, you can send the post data but it won't redirect you to the page you send the post data, as far as I know. I think the most viable is having another form besides the one the user needs to select the option and send that with the post data that you want.