Hi Critical Bill,
Sorry to inform you, but the missile bug/feature is all part of a feature intoduced in the R:TW engine which forces certain units, such as legions, to charge post missile throw. Sorry.

When your, brilliant, general gains the night-fighter trait, in the right-hand bottom corner of the battle-deployment scroll, you will see a little button which asks you if you want to fight at nights. Simply tick it and start the battle to experience on of the best parts of BI!

On the pre-battle screen you may see enemy re-inforcements greyed out after you click the button, but it's nothing to worry about, all it means is that the usurper and evil enemy leader for that army won't be turning up in the fight as he doesn't have the night-fighter ability - armies lead by captains will always have this problem! However, beware, the AI may do the same to you!

Hope this helps, cheers!