[Tsuarok]

Ok, hypothetical situation.

I am flying along in my astral self when I notice a small gang mugging your mom.  One of the members is a gnomish ghoul, and is thus attackable; the others are completely mundane.  I attack the ghoul and knock her out.  She's permanently dual natured, so I should still be able to interact with her. 

Can I pick her up and use her as an improvised club to attack the mundanes?

[Mirikon]

No. You can affect astral forms, but you could not grab a dual natured creature's astral form, and use that to control the body.

[Tsuarok]

ah... then combat vs a dual natured being cannot attempt knockdowns and such?

[Xzylvador]

I was wondering about this too. IMO, the rules for Astral Combat are complete crap... or I should probably say the lack of rules.
"Just like Melee Combat" is really quite useless in a world where everything is made of energy and movement happens at the speed of thought.
One of the problems is the "always dual natured" state of creatures like ghouls or an adept with assensing. If your astrally projecting mage is hovering 30 meters above, can he just bombard at-will with low-drain mana spells without a chance of retaliation?

So the way I see it, astral combat are all pretty much attacks of will. If you can see it, you can "hit" it; regardless of the way you normally fight. You put your mind to "harm XX" and XX puts his mind to "defend against XX" and that's pretty much it. The whole "like melee combat" thing I consider to mean: "Attacks are complex actions, range does not count, friends in melee rules apply, defend with your combat skill." Knockdown and stuff could probably exist, they'd be more like mildly stunning your opponent for a while so his mental defense is lowered.

[Tsuarok]

Just because I like to have things cited, I found this in SM (p.126) which strongly suggests that my scenario wouldn't work:

Awakened ivy is exactly what its name implies: a species
of the typical ivy vine that is dual natured. Because it is dual
natured, it has an active astral form and acts as a barrier to
other dual-natured or astrally-projecting beings. To a dualnatured
being, awakened ivy is little more than an annoyance.
If the vines are physically moved out of the way, the
ivy’s astral form is moved also. Astrally-projecting beings that
cannot materialize, however, have no way to move the physical
vine out of the way, leaving them with only one option:
astral combat.