Exchange 5.5 to 2003 migration problems....55 mailboxes disappeared

[pathaide]

We are currently migration from NT 4 to Windows 2003 as well as Exchange 5.5 to Exchange 2003. We have completed the Windows 2003 migration and are currently running AD with no issues. We installed the ADC connector via the wizard and ran through all the tools (mailbox resource wizrd, etc) once and found that we had the same accounts as the primary on multiple mailboxes which apparently is not supported under Exchange 2003. This created all sorts of disabled windows accounts. What we did next was to remove all the connectors, change the primary accounts on the affected mailboxes, delete the disabled accounts and re-run the ADC. Once we did this and hit replicate now, all those mailboxes were deleted. After speaking with Microsoft, we found out that the ADC stamps the resource mailbox with ADC global attribute and we needed to remove that. They say this is a bug of some sort in the ADC.

My question is this....is there a better way to perform this migration where I don't risk having accounts deleted automatically? We have 9 sites (in one organization) to migrate and we can't afford to have anything like this happen again. What are the best practises? Any help would be greatly appreciated

Thanks