Includeusersecurity across site collections

I don't know if migrating user security from a site collection to another one is not supported or I'm missing something. I have two site collectionshttp://abc.com/ and http://xyz.com. I use STSADM Import/Export along withIncludeusersecurity parameter to export then import from http://abc.com/site/ or any sub-site beneath http://abc.com site collection. This case works. But If I import an exported document library/list tohttp://xyz.com or any sub-sites beneath http://xyz.com site collection. I've not tried any 3rd party migration tool but I think these tools do support migrating components with security setting across site collections. One of the requirement would be the use of script (PowerShell or STSADM), not 3rd tool.

Has anyone had the same issue?

Thuan Soldier
A 23-year-old man loving Microsoft technologies and making crazy ideas on business journey.
SharePoint Vietnam | Blog | Twitter