Can you provide a cite for that? Because the only creature I was able to find that combined natural and manufactured attacks into a single routine was the Werewolf Lord, and he explicitly gives up his 2 claw attacks in favour of a bastard sword attack.
http://www.wizards.com/default.asp?x=dnd/rg/20070403a and
http://www.wizards.com/default.asp?x=dnd/rg/20070410a specifically reference a monk being able to make his normal unarmed routine (which is treated as a manufactured weapon) and then do all the natural attacks as secondary natural weapons (so the attack is at -5 and they only add 1/2 Str to damage). If you can weed out the bad stuff (mostly the poster Aelryinth) from
http://community.wizards.com/go/thr...ist_of_the_Forest?post_id=474713553#474713553 you'll notice that they exhaustively cite rules for making standard iterative attacks and then doing naturals at -5.
http://www.d20srd.org/srd/specialAbilities.htm#manufacturedWeapons is the primary source for that and is listed and quoted in that thread.
If it's just about the part where attacking with a manufactured weapon and a clawed appendage wielding that weapon then... I actually can't find anything anywhere explicitly saying the claw attack can't be used in general. The
Lycanthrope template does say in it that "A hybrid may attack with a weapon and a bite, or may attack with its
natural weapons." but that only refers to the hybrid lycanthrope form and not every creature ever.
http://www.giantitp.com/forums/showthread.php?t=207742,
http://www.minmaxboards.com/index.php?topic=482.0, and other places do refer to not being able to use the clawed limb for a claw attack while wielding a weapon in the claw but I can't find the exact rules quote.
Well, I can find stuff saying you can't make a secondary claw attack after you've used the limb for a primary attack.
http://www.wizards.com/default.asp?x=dnd/rg/20070403a has it with the paragraph "A creature can choose to treat its unarmed attacks as its primary attacks and its natural weapons as secondary attacks. (This method is normally used to add weapon attacks to a natural attack routine.) The creature must make all unarmed attacks with its primary limb, which prevents that hand from being used for a natural attack such as a claw or slam."
There's also a bit from the FAQ saying that a Lizardfolk can't make a claw attack along with, say, an attack with a longsword in the clawed hand.
What happens when creatures use their natural
weapons as secondary attacks along with a manufactured
weapon? For example, lizardfolk have two claws that also
serve as hands. What happens when they wield a onehanded
weapon in one hand and nothing in the other? Do
they lose both claw attacks in exchange for their attacks
with the weapon?
Wielding a manufactured weapon doesn’t prevent a
creature from using all its natural weaponry, provided that the
creature is using the full attack action and the additional natural
weapons are free.
The example lizardfolk can’t make a claw attack with the
“hand” that holds its weapon, although it does get to attack
with the weapon itself. But, if it’s using the full attack action, it
can use its other claw as a natural secondary attack (–5 to
attack rolls, half Strength bonus), and can also bite as a natural
secondary attack. In effect, the lizardfolk is using its normal
full attack routine with the manufactured weapon attack
substituted for one claw attack.