[Update by Milbo: We recommened to use the almost foolproof Daycounts migrator http://extensions.virtuemart.net/import-export/virtuemart-migrator-detail]
After several migration attempts through combination of methods found online, finally got a working approach that successfully migrates Joomla 1.5.x to 2.5.4 and VM1.1.x to VM2.0.6. Doing this for my future ref as well as assisting those who're still in need of a working approach for both joomla and virtuemart migration
Step0: Do this migration on a test site, before moving it to a live site after testing.
Step1: To reduce complication, I have strip Joomla of all unnecessary extension and kept only VM and Akeeba Backup in place, and selected default template that comes with Joomla original install.
Step2: Patch Joomla to latest 1.5.26 (patch up one version at a time using FTP to patch 1.5.x version to latest version
(stable patched package can be found @ http://docs.joomla.org/Joomla_1.5_version_history#Joomla.21_1.5.22
Step3: Patch VM1.x to 1.1.9 (patch can be found @ http://virtuemart.net/downloads
Akeeba Backup (Name your backup to indicate a patched Joomla and VM version)
Steps4: Migrate Joomla First (install Jupgrade @ http://extensions.joomla.org/extensions/migration-a-conversion/joomla-migration/11658
), go through the migration with the guide steps. You will notice that VM is not migrated to the new jupgrade folder, it is ok at this stage not seeing your VM in the new Joomla 2.5 under newly created jupgrade folder.
Akeeba Backup (Name your backup to indicate upgraded Joomla and old VM version)
Step5: Upgrade VM using this guide (http://dashhelp.com/tutorials/joomla-tutorials/75-migrate-virtuemart-1-1-9-to-version-2-0-updates
) in the new Jupgrade admin folder (www.yoursite.com/jupgrade/administrator
etc), in addition to following the guide in moving VM product images folder to "/var/www/yoursite/images/stories/virtuemart" folder, also create an identical copy in "/var/www/yoursite/jupgrades/images/stories/virtuemart". This image move is required before VM2.0.6 migration. If you have done the migration and did not see the image related to the product, doing the migration again will not help fix it. You will need to restart the step 5 process from last akeeba backup,(drop all database before restore, i decide to drop the DB for simplicity although only certain tables are required to be cleared)
Akeeba Backup (Name your backup to indicate upgraded Joomla and Upgraded VM version)
Step6: Clean your web folder, and restore your new site at intended "var/www/yoursite/"
- I use "https://www.akeebabackup.com/download/official/akeeba-kickstart.html
" to restore
Hope this guide help save you some time.