Installing Mavericks in VirtualBox

I would like to install Mavericks in VirtualBox. I tried different solutions but I can’t get this work. First I downloaded Mavericks from the app store.

Then I converted the InstallESD.dmg to an ISO using the Disk Utility and then renaming the file. But when I tried to boot I get this error in VirtualBox:

Fatal: No bootable medium found! System halted

And happened the same when I created the ISO with this script

#!/bin/bash
ESD=$1
TMP=$2

if [ -z "$ESD" ] || [ -z "$TMP" ]; then
    echo usage: "'$0' /path/to/esd /path/to/tmpdir"
    exit 1
fi
if ! [ -e "$ESD" ]; then
    echo "file '$ESD' does not exist"
    exit 1
fi
if ! [ -e "$TMP" ]; then
    echo "dir '$TMP' does not exist"
    exit 1
fi

MPAPP=/Volumes/install_app
MPIMG=/Volumes/install_img
IMGSPARSE=$TMP/install.sparseimage
IMGDVD=$TMP/install.cdr

detach_all() {
  if [ -d "$MPAPP" ]; then hdiutil detach "$MPAPP"; fi
  if [ -d "$MPIMG" ]; then hdiutil detach "$MPIMG"; fi
}
exit_all() {
  echo +++ Command returned with error, aborting ...
  exit 2
}

trap detach_all EXIT
trap exit_all ERR

echo +++ Trying to unmount anything from previous run
detach_all

echo +++ Mount the installer image
hdiutil attach "$ESD" -noverify -nobrowse -readonly -mountpoint "$MPAPP"


echo +++ Convert the boot image to a sparse bundle
rm -f "$IMGSPARSE"
hdiutil convert "$MPAPP"/BaseSystem.dmg -format UDSP -o "$IMGSPARSE"


echo +++ Increase the sparse bundle capacity to accommodate the packages
hdiutil resize -size 8g "$IMGSPARSE"

echo +++ Mount the sparse bundle for package addition
hdiutil attach "$IMGSPARSE" -noverify -nobrowse -readwrite -mountpoint "$MPIMG"

echo +++ Remove Package link and replace with actual files
rm -f "$MPIMG"/System/Installation/Packages
cp -rp "$MPAPP"/Packages "$MPIMG"/System/Installation/

echo +++ Unmount the installer image
hdiutil detach "$MPAPP"

echo +++ Unmount the sparse bundle
hdiutil detach "$MPIMG"

echo +++ Resize the partition in the sparse bundle to remove any free space
hdiutil resize -sectors min "$IMGSPARSE"

echo +++ Convert the sparse bundle to ISO/CD master
rm -f "$IMGDVD"
hdiutil convert "$IMGSPARSE" -format UDTO -o "$IMGDVD"

echo +++ Remove the sparse bundle
rm "$IMGSPARSE"

echo "Done"
echo "Find your DVD at '$IMGDVD'"

I also created a booteable pen drive with the information here and I mounted it as a virtual disk. But again VirtualBox throws an error when I try to mount the image:

Failed to open the hard disk file /Users/username/Documents/usbdrive.vmdk.

Could not open the medium '/Users/username/Documents/usbdrive.vmdk'.

VD: error VERR_RESOURCE_BUSY opening image file '/Users/username/Documents/usbdrive.vmdk' (VERR_RESOURCE_BUSY).

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: Medium
Interface: IMedium {05f2bbb6-a3a6-4fb9-9b49-6d0dda7142ac}
Callee: IVirtualBox {fafa4e17-1ee2-4905-a10e-fe7c18bf5554}
Callee RC: VBOX_E_OBJECT_NOT_FOUND (0x80BB0001)

I think this is answered by Mark at:

https://apple.stackexchange.com/questions/106476/how-to-install-os-x-mavericks-in-virtualbox#

I normally would include a summary to external sites (but it's a StackExchange site).