(I started this question with the title "How do you manipulate material components when using Somatic Weaponry?" but I realized the current title is more appropriate)
This is along the lines of this great but with no accepted answer question Does Casting a Spell with Somatic and Material Components Require 2 Hands?
Me and my friends always ruled that in order to cast spells with material components you need a free hand in order to manipulate them, but it can be the same hand used for the somatic component. Or better, we've always been confident it explicitly stated that on the rulebooks
Now we are wondering what happens if you have somatic weaponry and, for example, wielding 2 rods (or 2 of most one handed stuff actually). We are actually divided into 2 groups:
One group says that without being able to manipulate material components Somatic Weaponry would be useless (because you'd still need a free hand) and since a material components are not that big usually they can be manipulated with a busy hand (like a hand wielding a rod or a weapon or something else) so if you have somatic weaponry you can cast material components spells even if both hands are wielding something (of course not including 2h weapons which you can detach your hand from in order to cast).
The other group says that if this was true not only eschew materials would be rendered useless (well, more useless according to some people) but somatic weaponry would've actually given the benefit of one and a half feats: Somatic Weaponry itself and partly Eschew materials (since you'd be able to cast spells with both hands busy), on top of that since it's a gameplay (it affects the casting of spells) issue and not a plausibility issue (it's plausible to hold most material components with 2 fingers even though some manipulations descripted in some spells are really not doable with a busy hand) we can't be the ones drawing the line between what's too big to be manipulated with a busy hand and what not
In the end the discussion shifted into wheter you need a truly free hand (that is, a hand that is gameplay-wise considered free) to manipulate material components or not (that is, you can manipulate a material component even with a hand wielding something else)
And that's how my "search for the truth" starts Since I like things to be as RAW as possible whenever reasonable, I started doing some research on the subject.
First I discovered that it's not actually true the rulebooks explicitly say you need a free hand for material components nor that the free hand can be the same of the somatic components.
Then I found this http://archive.wizards.com/default.asp?x=dnd/rg/20040810a which states (I tend to consider "rules of the game" and "FAQs" articles not "official" but claryfing when needed):
Your hand is free when you aren't carrying a weapon, a piece of equipment, or (usually) a shield. You can strap a buckler to your arm and use your hand to wield a weapon (albeit at a penalty), so there's no reason you couldn't use your buckler hand for a somatic component. The buckler might interfere a little bit, but that's what the arcane spell failure chance for the buckler is for. You also can strap a light shield to your forearm and still carry items in that hand, but you can't use the hand for anything else (such as wielding a weapon), so there's no good reason you should be able to use that hand to complete a somatic component. Since manipulating a material component (including a focus) is part of casting the spell, it's best to consider the hand that holds the material component or focus as "free" for purposes of completing a somatic component
This paragraph actually says 2 important things:
1) When a hand is considered free (particularly when a hand is considere free for somatic components)
2) A hand holding a material component is free for completing a somatic component
Point #2 is similar but at the same time the opposite of what stated by the 2nd group (a hand used for somatic components can be used for material components), for this reason it doesn't answer my question wheter or not you need a free hand for material components
Then I found this very similar text on the FAQs and the Rules Compendium.
Spell casting creatures
Sometimes a creature can cast arcane or divine spells just as a member of a spellcasting class can. Such a creature can activate magic items accordingly. It’s subject to the same spellcasting rules that characters are, except as follows. A spellcasting creature that lacks hands or arms can provide any somatic component a spell might require by moving its body. Such a creature still needs material components for its spells. The creature can cast the spell either by touching a required component that isn’t in another creature’s possession or by having the required component on its body. Spellcasting creatures sometimes utilize the Eschew Materials feat to avoid having to use some material components. A spellcasting creature isn’t actually a member of a class and doesn’t gain any class features unless its description says otherwise
Chapter 10 in the PH says a spellcaster must have one hand free to cast a spell with a somatic component, and the caster must have any material components in hand already if he doesn’t have a free hand. So, how does a creature like a naga cast spells at all? Nagas don’t have hands!
Creatures that have hands need at least one free hand to cast spells with somatic or material components (or both). Creatures, that don’t have hands don’t need hands to cast spells (see page 315 in the MM). They use body movements to complete somatic components and use material components either by touching them (but not if they’re in another creature’s possession) or by having them somewhere on their bodies. A naga might carry material components stuck to its scales or even temporarily swallow them.
Does this apply only to spellcasting creatures? This paragraph/FAQ seems to assume that as long as there's contact with the material component and your body (or the insides of your body apparently) then you can cast the spell. And this, at least for me, brings more questions than answers
And so finally I'm here, asking you if there's a answer to my questions:
1) Do you need a truly free hand in order to manipulate material components?
2) Can you have your material components strapped around your body so that you don't have to hold them in your hands? Seems pretty weird (and gross) to me and defies not only the logic of some spells (Tasha's Hideous Laughter and its tarts come to mind) but the fact that rulebooks say you need to manipulate the components...and yet the rules (the rules compendium nonetheless) seem to say so. Does this apply only to creatures with spellcasting powers or can limbs provided creatures do that too?