It sounds to me like you want to customize the stylesheet for this one. It's best to add a role to the list, then using CSS to customize how it appears.
[horizontal.flags]
label:: value
Then style the "flags" CSS class.
> Also, how do I cancel the [horizontal] style specification after it is invoked?
I'm not sure what you are asking here. Could you restate?
Cheers,
-Dan