I'm being annoying now I'm sure... but lets look at another situation and try to find a complete answer;
Let us assume that a combat gets underway that includes 5 chaos terminators with one or more models with power mauls (as they are an obvious example for models with such weapons) and 5 GK paladins (mixed weapons, it doesn't really matter).
For the sake of arguement we will say that the GK paladins have some models which strike BEFORE the chaos terminators (ie: halberds). they make their attacks at their "normal" initiative step (modified by their unique halberds of course) as we are told they must.
Following this, the chaos terminators strike - and (again for the purposes of this) a number of wounds are caused by models with power mauls. The GK player allocates the power maul attacks to the halberd wielding paladin models which have already attacked. A paladin is wounded but not killed, and because of the "concussive" rule his initiative is reduced to 1.
we continue down the initiative steps and come to initiative 1. This initiative step now includes any paladins that might have daemon hammers AND the paladin that has been reduced to initiative 1 by the "concussive" rule.
According to THIS:
The Assault Phase:
Who Can Fight? BDB pg23 notes that a model that is engaged in combat MUST fight when it's initiative step is reached.
All models must fight. and according to the concussive rule, the paladin is now I1,
Special Rules:
"Concussive" BDB pg35
So, am I correct in assuming that the model, armed with a halberd that has already attacked at an earlier I, now MUST attack again at its new I1!?
I cannot find a passage in the assault rules to say otherwise. Please help me find it!!!