Fraction of a HD and Smite

[Flyspeck23]

Ok, I'm applying templates for summoned creatures right now (as some of you might've guessed, 'cause of my last thread, dealing with celestial vermin). Anyway, here's my problem:

A raven's got 1/4 HD (d8, if you need to know). Smite evil/good (through Celestial/Fiendish template) adds the creature's HD to damage once per day.
Now what? It's 1/4 HD, so do I round down (meaning that the smite does 0 extra damage, and is therefore redundant), or is it considered a single HD (but only a fraction of it is relevant for hp)?
A similar question could be asked for spell resistance (5+hd).

And once again, any official source?

 

[demiurge1138]

Nothing directly official, but the Player's Handbook says to always round fractions down. So I'd rule that a celestial raven would have a useless smite attack and SR 5.

Demiurge out.

 

[Matafuego]

I agree
And I like celestial ravens... they sound cool