In an effort to help, from page 296 of SR4A:
QUOTE
If the critter is dual natured, Natural Weapon may be used with the normal Unarmed Combat skill and physical Damage Value to perform attacks against astral opponents (within reach).
I know Astral Combat rules are kind of weird, and I cannot say with perfect certainty why all the changes were made, but I can make some reasonable guesses. For one, a continuing effort on restricting magical skills to magicians - which began back in 2nd/3rd edition or so. Unfortunately, blanket bans mean that some strange situations come up when, for example, authors forget to give dual-natured critters the Astral Combat skill. Efforts to correct that problem go in...different ways. For example, you'll note in
Runner's Companion that all the sapient critters and drakes can buy Assensing and Astral Combat, since they're all Awakened...even if they aren't magicians.
Running Wild is even weirder and honestly I don't know what the thinking was when somebody wrote those rules, although if you ever hear Aaron and I argue about dual-natured vs. Dual-Natured you probably will grasp something of the minutae we're dealing with.
Long story short: SR4 was a big rules system change, there was bound to be some fallout.