Failsafe method to create NetInstall image of pre-configured MacOSX

Hi All

I am trying to create NetInstall image of a pre-configured MacOSX install(mid-2011 mac mini) in this case. Here is my workflow:

1. Setup base OSX Mountain lion

2. Do all updates and configure System Preferences and Finder Preferences as desired

3. Install all desired software to be packaged with the system

4. Boot into target mode and then use a second mac mini running Casper Composer to create a .dmg of the OS.

5. Copy the finished .dmg to ML Server

6. Try to use System Image utility to create a NetInstall image that other mac minis can then use as base install

I havent had any success so far creating a valid .nbi folder I can use(and that works) for re-deployment unless I use Casper Admin and Casper Imaging to manage this. The reason I am trying to get away from using them is that the differnece between buying a $70 Casper Composer(or using the free Disk Utility) and buying the full Casper Suite is considerable. Also, my understanding of System Image Utility is that:

1. It should be possible to build a customised image of OSX from base with packages and coonfiguration added but it doesnt seem to work

2. NetInstall is the only viable option for what we want to do as NetBoot presumes you will boot off the image each time you start up(which is not what we want - we want the ability to clone systems and from bare metal if necessary) and NetRestore flatly doesnt seem to work from .dmgs.

Here is what I have found:

a) I can create NetInstall images from a mounted downloaded Apple-provided OSX Installer that work but as soon as I put customisations in them, the customisations fail.

b) By default NetInstall is greyed out when you mount the dmg and use it as a source in System image utility. Suggestions online are to change the Source to use a New variable and then point it back at the same location. NetInstall is then available. If you try to create a .nbi from this, you get an error saying that there isnt enough space on the target drive - the uncompressed dmg is about 7GB max and there is a spare 60-70Gb free on the drive I am trying to create the image on.

c) I have tried manually creating the .nbi folder but the instructions I found at http://support.apple.com/kb/TA21133 for doing this are outdated as they apply to ppc firmware and although I suspect the technique will still work, I cant work out which elements of the i386 folder I need to retain/move. Copying the i386 folder from another working Netinstall folder doesnt help.

d) I found some links suggesting that NetInstall only worked when the OSX versions were identical so I tried to run the System Image Utility on the Mac where the dmg was created. Here I get two errors:

i) If I just run the NetInstall using the default source, it errors saying an unknown error has occurred and get the following in the log:
Workflow Started (2013-08-21 11:39:45 +0100)

OS X 10.8.4 (12E55), System Image Utility 10.8.3 (624)

Starting action: Define Image Source (1.4)

Finished running action: Define Image Source

Starting action: Create Image (1.7.2)

Starting image creation process...

Create NetInstall Image

Failed to validate the install type!!! Error: The source volume is not an OS X 10.8 volume.

An unknown error has occurred.

An unknown error has occurred.

Image creation process finished...

Stopping image creation.

Image creation failed.

ii) If I change the source to the .dmg file and unmount it quickly to avoid any file locks, the installer goes further and seems to almost finish but then gives the following error(just appending the final bits):

+ echo 'Detaching disk image'

Detaching disk image

+ '[' DEBUG == DEBUG ']'

+ /usr/sbin/lsof +fg /tmp/mnt.UJaQAiTy

COMMAND PID USER FD TYPE FILE-FLAG DEVICE SIZE/OFF NODE NAME

mds 36 root 24r DIR R,EVO 1,5 306 2 /private/tmp/mnt.UJaQAiTy

+ '[' '/dev/disk1s2 on /private/tmp/mnt.UJaQAiTy (hfs, local, nodev, nosuid, nobrowse)' '!=' '' ']'

+ /usr/bin/hdiutil detach /tmp/mnt.UJaQAiTy

"disk1" unmounted.

"disk1" ejected.

+ /bin/rmdir /tmp/mnt.UJaQAiTy

+ return 0

+ '[' '' '!=' '' ']'

+ /bin/rm -r '/Users/admin/Documents/NetBoot of Untitled 1.nbi/i386'

+ /bin/rm '/Users/admin/Documents/NetBoot of Untitled 1.nbi/NetInstall.dmg'

+ /bin/rm '/Users/admin/Documents/NetBoot of Untitled 1.nbi/System.dmg'

+ /bin/rmdir '/Users/admin/Documents/NetBoot of Untitled 1.nbi'

+ exit 1

Script is done.

Bridge exited with status 256

Failed to create image from restore source.

An unknown error has occurred.

An unknown error has occurred.

Image creation process finished...

Stopping image creation.

Image creation failed.

Anyone have any idea how I can get around these issues?