Firstly: root:wheel refers to ownership (user:group) not permissions
Originally Posted by Davvido
The permissions are written something like this: rw-r-r
Secondly, you're on a mac - it being a unix based OS has a root account and a wheel group. This is why you can chown root:wheel on your mac.
There is no mobile account or mobile group on your mac. That is why the chown command fails.
Thirdly, I think you misunderstand the way the afcd service works.
ps -jA | grep afcd | grep root
root 212 1 212 c3501270 0 S ?? 0:04.80 /usr/libexec/afcd --lockdown -d /
ps -jA | grep afcd | grep mobile
mobile 202 1 202 c1f7f618 0 S ?? 0:00.82 /usr/libexec/afcd --lockdown -d /var/mobile/Media -u mobile
mobile 204 1 204 c1f7f3a8 0 S ?? 0:00.01 /usr/libexec/afcd --lockdown -d /var/mobile/Media -u mobile
What this means is you can connect to afcd for the entire iPhone filesystem and any file you copy is copied as user root.
This is why you *think* it is preserving file/group ownership, when it actuality the afcd service runs as root (which is what DiskAid uses to send files to the iPhone)
Or you can connect to just the /var/mobile/Media sub-area of the filesystem and any file you copy is copied as user mobile (this is how iTunes connects to the iPhone, even for non jailbroken iPhones)
DiskAid actually allows you to choose between the two, in the lower left hand part of the DiskAid window.
Still no way to set "permissions" they are taken from the default umask. However what I have explained partly solves the "ownership" problem.